Fish Care

What are goldfish?

Goldfish (Family: Cyprinidae, Species: Carassius auratus) are a common freshwater and coldwater fish, descendant of the carp. Carp were the first ornamental fish to be kept, and, in about 960, the first carp pond was recorded. Our modern goldfish are actually domesticated Crucian carp from the slow-moving waters of China. The red and white goldfish was first developed in 12th-century China by selective breeding of the occasionally colorful carp that would otherwise be destined to be dinner on their plate! Goldfish were introduced to England in the 1600s, where they, and the hobby, began its long road to popularity.

Goldfish are extremely enjoyable and rewarding when kept as pets, as long as their requirements are met. Goldfish have an average life span of 12 to 20 years and there are of many varieties and colors, such as the Fantail, Pearlscale and Black Moor.

Koi, which also descended from carp, are not goldfish. Koi and goldfish come from the same family, Cyprinidae, but their genus and species differ; Carassius auratus for goldfish and Cyprinus carpio for koi. Notice that koi have “whiskers” aka barbels, while goldfish do not.

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How long do goldfish live?

The average life span of a goldfish is upwards of 12 years. They can live much longer, even up to 20 years of age, when given the correct environmental conditions. Taking on the responsibility of caring for a goldfish is quite a commitment!

Goldfish are all the same, right?

No! There are many different kinds of goldfish! The most common or familiar goldfish seen in the fish stores and pet shops are Commons or Comets, and unfortunately are often used as ‘feeder fish’. The “non-fancy” goldfish are long-bodied. The Comet is similiar to the Common but has a longer tail.

There are many fancy breeds of goldfish, including Orandas, Telescope-eyes, Celestials, Lionheads, and more. Fancy goldfish are round-bodied fish and some have “popped” or “telescope” eyes (e.g. Moors), eyes that only gaze upwards (e.g. Celestials), and some that have an arched back (e.g. Ryukins). Fancy-type goldfish have different needs than the Comet with respect to temperature and environment. For example, the Bubble-eye goldfish with its’ massive sacs underneath the eyes requires a tank enironment with no jagged or pointy objects, so that the sacs will not get punctured. Before buying your goldfish, always perform research on its’ specific needs, so that you can best provide its’ correct environment!

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Is it still a goldfish if it isn’t gold?

Yes! Goldfish come in many colors – red, white, brown, black, gold, yellow, orange, or a combination of these colors.

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Why has my goldfish changed colors?

Goldfish may change colors as they mature. Black, for example, is a very unstable color in goldfish and will usually fade over time, often to be replaced with a gold or orange color.

The following shows color change in another goldfish over time.

If you notice new black or brownish spots appearing on your goldfish, these may be ammonia burns! Likewise, you may see red lines on the tail or fins as a result of elevated ammonia. Test the water parameters, especially the ammonia level, and if the ammonia level is measurable, add AmQuel® at the rate of one teaspoon (one capful) per every ten gallons of water and/or perform an emergency 50% water change. If you don’t have a testing kit available, then take a sample of your water to your local fish store and ask them to test it for you (for pH, ammonia, nitrite, nitrate and KH/alkalinity). This is usually done for free! Be sure to ask for the exact readings, so that you can provide appropriate corrective action and in the event that you need some assistance on-line, you will be able to post the results. Otherwise, in our experience, workers at the local fish store sometimes erroneously say that the ‘water’s alright’, even in the face of measurable toxins. Ammonia burns will heal over time with a series of small water changes and the use of AmQuel®, in order to keep the ammonia level at zero.

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Is it still a goldfish if it isn’t gold?

Some goldfish normally have a head growth or “wen”. Lionheads grow wens on the top of their heads, while Orandas grow wens all around their heads, so that only their eyes and mouth can be seen. Wen growth may begin around 6 months of age and continue for longer than 2 years.

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What are the names of my goldfish’s fins?

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What does the inside of my goldfish look like?

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Is my goldfish male or female?

There are a few ways to sex goldfish. This is best done after the fish has reached sexual maturity, which may occur anywhere from 9 months to 2 years after hatching. This is easiest to accomplish during breeding, when males chase and nip at females. The males also develop “breeding tubercles”, which look like small white spots or pimples on their gill covers and this should not be confused with the parasite, Ich, which would also be on other areas of the body. It is possible for females to develop tubercles, but this is rare and they develop fewer than the males do. During breeding, the female goldfish’s body may become larger, indicating that she is carrying eggs.

The most reliable method of determining your goldfish’s gender is by examining the fish’s vent (anal opening), which is located under its’ underside between the tail and anal fins. If the vent sticks out a bit, you have a female. A male’s vent does not stick out, but instead goes inward.

In general, females are usually larger in body and have larger anal fins than males. Males usually have thicker and longer pectoral fins than females.

Another sexing technique, which is not very reliable, looks at symmetry of the goldfish’s body. With this technique, when viewing the goldfish from the top down, the sides of the male’s body are more narrow and symmetrical, while the female’s sides are more broad and asymmetric.

If all else fails, the following method may make your goldie’s gender more clear… 🙂

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Why can’t I keep my goldfish in a bowl & how much water does my goldfish need?

Goldfish need at least 10 gallons of water each, and the larger goldfish require as much as 30 gallons per goldfish in order to remain healthy and thrive. They are an active fish requiring space to maneuver and swim in. Goldfish also require filtration and aeration of the water. These provide movement of the water’s surface, allowing for oxygen exchange, so that the water becomes better filled with oxygen. Goldfish need a lot of dissolved oxygen in the water. Typically, a goldfish tank’s filter system should turnover the tank’s water a minimum of 10 times per hour… a far cry from what happens in a goldfish bowl!

Goldfish pass a lot of waste, in the form of ammonia, mostly via respiration across their gills. This and other harmful chemicals, such as nitrite and nitrate, that you can’t see, will build up in the water quickly. If the levels of ammonia and nitrite are above zero, the fish may become quite ill or even die. Ammonia will build up in less than one day in a goldfish bowl! When your goldfish lives in a higher volume of water, it is easier to maintain proper water quality, when these chemicals are being produced in the water. Your goldfish’s proper-sized tank should be cycled and nitrate levels kept at less than 20 ppm.

You may have seen some goldfish living in bowls that appear to be fine but they really aren’t! They are under constant stress from the chemicals, and the stress compromises their immune system, which will eventually lead to illness and death. Under such conditions, their growth is often stunted. Goldfish under normal conditions grow to be quite large, easily reaching 6 inches and some will grow to 12 inches or more. Some of the larger goldfish eventually need as much as 30 gallons each as they grow and need proper tank space in order to be able to swim. Goldfish are innately schooling fish, so do better when kept in at least a pair. Therefore, in order to meet all of these needs, we recommend that the minimum tank size required for one to two grown non-fancy goldfish (e.g. Common, Comet), who grow to 8-12″ is a 55-gallon tank (48″ x 13″ x 20″), while the minimum tank for one to two grown fancy-type goldfish, who grow to 6-8″, would be a 20-gallon “long” tank. Any of these goldfish may grow larger than the averages stated here and would therefore need even larger tanks or to be housed in a pond. Remember though that bigger is better!

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What kind of water should I use?

For the vast majority of keepers, it is perfectly fine to use tap water, which is inexpensive and convenient. You will need to “condition” the water with water conditioning products, that can be bought from your local fish store, which remove toxic chlorine, chloramines, ammonia and heavy metals. Test your water for pH, ammonia, nitrite, nitrate and carbonate hardness/alkalinity (KH), so that you know what the baseline parameters are of your water. Either purchase testing equipment (for pH, ammonia, nitrite & nitrate) and perform the testing yourself or have your local fish store do it. They will most often do it for free but remember that they are not open late at night when you might urgently need to know what your water parameters are. It is very handy to have water testing equipment at home and really a must when keeping goldfish!

You may wish to use bottled ‘spring’ water but this can be expensive and inconvenient and often this type of water is overly acidic and it may have had the natural minerals processed or removed from it. Fish need the minerals that are naturally occurring in water to remain healthy. If you must use a processed type of water, such as distilled water or reverse osmosis (RO) water, you will have to use a product that replaces the minerals lost.

If you use well water, you should measure the parameters of it seasonally to determine if any changes have occurred. For instance, some farming areas have varying readings due to the raising cattle or use of chemical fertilizers, which affect the local water tables and you may, for instance, see measurable nitrates.

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What kind of water should I use?

For the vast majority of keepers, it is perfectly fine to use tap water, which is inexpensive and convenient. You will need to “condition” the water with water conditioning products, that can be bought from your local fish store, which remove toxic chlorine, chloramines, ammonia and heavy metals. Test your water for pH, ammonia, nitrite, nitrate and carbonate hardness/alkalinity (KH), so that you know what the baseline parameters are of your water. Either purchase testing equipment (for pH, ammonia, nitrite & nitrate) and perform the testing yourself or have your local fish store do it. They will most often do it for free but remember that they are not open late at night when you might urgently need to know what your water parameters are. It is very handy to have water testing equipment at home and really a must when keeping goldfish!

You may wish to use bottled ‘spring’ water but this can be expensive and inconvenient and often this type of water is overly acidic and it may have had the natural minerals processed or removed from it. Fish need the minerals that are naturally occurring in water to remain healthy. If you must use a processed type of water, such as distilled water or reverse osmosis (RO) water, you will have to use a product that replaces the minerals lost.

If you use well water, you should measure the parameters of it seasonally to determine if any changes have occurred. For instance, some farming areas have varying readings due to the raising cattle or use of chemical fertilizers, which affect the local water tables and you may, for instance, see measurable nitrates.

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Should I ‘condition’ the water?

Yes! Conditioning the water removes dangerous chemicals like chlorine and chloramines and will neutralize toxic ammonia and heavy metals. These chemicals can all be harmful and even deadly to fish. For example, ammonia poisoning burns the gills and sensitive mucous membranes of the fish’s skin, mouth and intestines and even the corneal covering of the eye.

AmQuel® is a water conditioner, which removes chloramines, chlorine and ammonia. While letting a never-seen-soap bucket of water sit uncovered for 24 hours will allow chlorine to evaporate, it does not allow chloramines to evaporate. Chloramines can only be removed by using water conditioners specifically designed to do so. You can contact your local water supplier to find out if your tap water contains chloramines, to determine if you need to use AmQuel®.

When using AmQuel®, ammonia will be detoxified. This means that it is still present in the tank but in a non-toxic form, so it will not harm the fish but it will still allow the cycling process to continue on. When using AmQuel® as a water conditioner, be sure to get an ammonia tester that is compatible with AmQuel®, to measure the amount of remaining toxic ammonia, that is, a salicylate-based tester, such as Aquarium Pharmaceutical’s ammonia tester.

Prime™, handles toxic ammonia and as well, detoxifies nitrites and nitrates, but only at higher dosages. AmQuel Plus® detoxifies nitrites and nitrates, but AmQuel Plus® also leaves nitrites and nitrates unmeasureable, so one is left guessing where they are in the cycling process as well as when to perform regular water maintenance, which is based upon nitrate level measurements.

The water conditioner, NovAqua®, removes toxic chlorine and heavy metals, adds a protective coating to the slime coat as well as a tiny amount of sodium chloride (salt). If your water supply does not contain chloramines, you could just use NovAqua® alone. Yet, given the goldfish’s large output of ammonia, it is still recommended to use AmQuel® in combination with NovAqua® because of its’ added benefit of taking care of toxic ammonia. Both AmQuel® and NovAqua® can be used at the rate one teaspoon (one capful) for every ten gallons of water.

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What is ‘topping-off’ and can I do it?

‘Topping-off’ is the process of adding water into a tank after some has evaporated without taking any additional water out first. Remember that the minerals and chemical toxins in the water do not evaporate, so if you do not remove and replace a portion of the tank’s water regularly, these may build up to toxic levels, which will harm your fish. It is fine to ‘top-off’ for evaporation as long as you are also removing a portion of the tank’s water on a regular basis, such as a 25% water change every week.

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What is goldfish salt and should I use it?

Goldfish salt is simply aquarium salt labeled especially for goldfish. In general, goldfish do not need salt in the water.

Salt may be added as a one-time dosage at the rate on of one teaspoon for every ten gallons of water when in the nitrite phase of cycling, to reduce nitrite’s toxic effects. Nitrite toxicity blocks normal oxygen uptake at the gills by forming methemoglobin. Salt (sodium chloride) is beneficial because its’ chloride ions compete with nitrite for transportation across the fish’s gills, and so, lessens the nitrite’s bad effects.

Salt is not a proper substitution for the treatment of such diseases as Ich, since there are safe and reliable medications that can be used.

There are varying opinions on the use of salt as a preventative. To date, there is no scientific proof of its’ value with the exception of a 1999 study by Dr. Altinok and Dr. Grizzle from the Department of Fisheries and Allied Aquacultures at Auburn University, in Auburn, Alabama. This study showed that none of the goldfish acclimated to a 3.0 or 9.0‰ salinity died when exposed to Flexibacter, while 66.5% of goldfish in only freshwater and 40.8% in a 1.0‰ salinity, died. This suggests a possible role of salt in the prevention of Flexibacter infection in goldfish, though it will not treat a Flexibacter infection that is already present.

If using salt, you should have a salinity meter (hydrometer) available to accurately measure the level of salt in the water. The addition of salt should be done gradually, since salt acts as an irritant to goldfish. Remember that salt does not evaporate from the water, so only add the correct proportion to the new change water. For example, if you put one teaspoon of salt per gallon originally in the tank, then you would only add one teaspoon of salt for each gallon of new water that you are adding back to the tank after a change and not dose the entire tank with salt all over again.

While you may read reports that salt, such as table salt, which contains iodine and/or anti-caking agents, should not be used, this is a myth. Table salt used at the amounts commonly used in freshwater aquariums in unlikely to be harmful and the small one-time dosage required during cycling would not be harmful. The one exception of salt that may be toxic to fish, is when sodium ferrocyanide (yellow prussiate of soda) is used as an additive. If you want to play it very safe, then use aquarium or rock salt.

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What temperature should I keep my goldfish at?

Goldfish are coldwater fish with a range in temperature from 60ºF to 80ºF. However, a temperature between 65º-75ºF is preferable with the fancy varieties preferring warmer waters of 75º-78ºF. Since tropical fish require a water temperature of 75º-80Fº, many are not compatible with the goldfish.

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Why do I need to do weekly water changes?

Once your goldfish’s tank has cycled, you need to maintain good water quality in order to keep your fish healthy. Fish naturally produce waste and chemicals, which can be harmful, and need to be removed. The end result of the nitrogen cycle are nitrates, which ideally should be kept at 10 or less, though up to 20-25 ppm may be satisfactory. It is through regular partial water changes that the nitrate level can be lowered. Typically, a 25% water change once every week will be sufficient.

If you notice that the ammonia and/or nitrite levels are measurable in a cycled tank, then this means that your current filtration system is not enough to handle the load of waste produced by your fish.

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How do I perform a weekly water change and maintenance?

First test for ammonia, nitrite, and nitrate. Ammonia and nitrites should read zero and the nitrates should be kept at 20 ppm or less, and ideally at 10 ppm or less. Nitrates are lowered through partial water changes with the amount and frequency of the change being dependent upon keeping your nitrate measurement at 20 ppm or less. Typically, a 25% change of water with conditioned, same-temperatured water will suffice. Measurable ammonia and nitrites will be lowered by the water change but suggest that there may be too many fish in your tank, that the tank is too little, that the filtration is inadequate or that the fish are being overfed. At the same time as the water change, vacuum 25% of the substrate using a “gravel vacuum” purchased at your local fish store. Each time that you do your tank maintenance, vacuum a different section of the substrate, so that you rotate them evenly. At this time, you may wish to scrape algae off the tank walls, if there is any present, and reorganize decorations, while being careful not to stir up the substrate too much. The next day, test the water parameters (ammonia, nitrite, nitrate) to make sure that you haven’t upset the cycle. If so, take corrective action for ammonia and corrective action for nitrites. If the nitrates are greater than 20 ppm, perform a 25% water change without vacuuming the substrate. This may be performed daily until the nitrates are 20 ppm or less.

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Do I need a heater in my tank?

The need for a heater depends upon the type of goldfish that you have. Such goldfish as the Common and Comet are coldwater and require no heater. Most fancy type goldfish, on the other hand, prefer the warmer temps of 75-78ºF and you may need a heater in order to keep your water temperature stable.

The need for a heater really depends on your individual situation. If you are in a climate or reside in a home where there are fluctuations in temperature of more than 2-3 degrees per day and you keep fancy goldfish or have goldfish that are or have been recently sick, then a heater may allow you to better regulate the water’s temperature. The non-fancy types of goldfish are less stressed by fluctuations in water temperature.

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What kind of decorations can I have in my goldfish tank?

You can use any aquarium safe decoration. Always check the label to make sure it says ‘for aquarium use’. Plastic plants, real plants, silk plants, driftwood, shells, or ceramic ornaments are great additions to the tank. It’s not recommended that you use wood, shells or rocks that you find at the lake or seashore, as these may contain parasite and diseases, which might be introduced into your tank.

When adding various woods, shells or terra cotta pots, be sure to measure the pH, to see if the decoration raises or lowers the pH of your water. You may wish to test it first, before even putting it into your tank. To do so, put the item in treated water and test the water daily for pH. With certain driftwood, you may find that the water turns brown and slightly cloudy and this is the result of release of natural tannins. They are not harmful and should clear up in a couple weeks.

Remember that as goldfish grow, some decorations will no longer allow your fish to fit through them, so keep this in mind and prevent your goldfish from getting stuck in one.

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What types of substrate should I use so that my fish won’t choke?

The best plan for substrate (covering of the bottom of the tank) would be to use large river rocks or sand, and a tank can even be left bare-bottomed.

Goldfish are always digging on the bottom of the tank for food, so the use of small gravel is not recommended because the fish will pick up the gravel in their mouths but sometimes the fish is unable to spit it back out. The rock or gravel can get lodged in its’ throat and the goldfish may choke to death. Remember that your fish will grow, so choose the size of your tank rocks accordingly. What may have been a large rock to a small goldfish, may turn out to be one that fits into its’ mouth as he grows up!

To keep sand out of your filter be sure not to have to have its’ uptake tube not too close to the sand. Keeping it at least 6 inches above the bottom, should keep sand out of your filter. Goldfish may eat some sand particles but these will pass without problem.

To make the transition from gravel to larger rocks in your tank, do so by slowly removing small portions of gravel over a few weeks to months, and replacing it with the new rocks. You might experience a slight re-cycling during this period, so be sure to measure your water parameters regularly during these changes. You could counter the re-cycling by putting the old gravel in a nylon stocking and keeping them in the tank for a short period of time. This allows the good bacteria, which has built up in the old gravel, to transfer to the new substrate. You can do this with all of the gravel at once, as long as you leave it in the tank in nylon stockings until the new rocks have built up their own good bacteria, but the slower method is safer.

If you are transferring to a bare tank bottom instead, you will want to do this very slowly, or else your tank will experience a significant re-cycle. If you ever need to nuke (tear down and disinfect) a tank, you should ideally add new substrate.

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What kind of plants can I put in my goldfish tank?

Can you say, “All-you-can-eat salad bar”?! 😉 You can put freshwater plants in your tank, as long as there is room for them and the tank has proper lighting but beware that goldfish love to eat plants! Don’t be surprised if you have to go back to the fish store for new ones often! Choices of plants for your goldie tank include java moss, java fern, swords, anubias, hornwort, cryptocoryne, hygrophila, onion plant, rotala, cabomba and bacopa.

You can choose plants that are touted as being not as palatable to goldfish, such as the java plants, as well as plants with hard or stiff leaves in an attempt to keep your goldies from devouring them. Very quick growing plants such as duckweed and anacharis may be able to grow faster than your goldfish can eat them. If your goldfish is fed a diet loaded with veggies, it might go after the tank plants less.

Plants will help to improve your tank’s water quality by consuming ammonia, nitrites and nitrates and add to the tank’s biological filter by providing more surface area for the good bio bugs to grow on.

When the lights go off at night, plants stop producing oxygen and instead use it up, Goldfish need more oxygen than most fish, so this might cause problems, especially if you have a heavily planted tank. Plants generally require 10-12 hours of proper florescent lighting (not incandescent lighting) each day to grow well.

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Does my goldfish need light?

Yes! Goldfish need light and it’s suggested that you keep them on a schedule of 12 hours with the light on, and 12 hours in darkness. They don’t have eyelids, so they need to have some dark to rest in. They “sleep” during the night. The use of florescent lighting is recommended over incandescent because it will heat the water less, is more economical and is required if attempting to grow live plants.

Remember not to place the tank in direct sunlight, which will heat the tank and promote algae growth. Be sure that there is a barrier (glass, acrylic or plastic), such as a tank lid between the light fixture and the water, so that neither you, nor your fish, will get an electrical shock!

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Does my goldfish tank need a lid?

Absolutely! All fish tanks should have lids. This prevents fish from jumping out, which often ends in injury and/or death. A lid also lessens water evaporation from the tank.

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What and how much should I feed my goldfish?

Goldfish should enjoy a good variety in their diet. Foods like specialized goldfish pellets and blanched vegetables, as well as frozen, live, or gel-based foods, provide good choices for you.

When you feed dry pelleted goldfish food, soak it first for at least five minutes in tank water or conditioned tap water to avoid swimbladder problems in your goldfish. Depending on the size of the pellet and the size of your fish, you may wish to feed 5-10 soaked pellets once or twice a day. Pre-soaking pellets makes sure that they expand outside of your goldfish and not inside him after he’s eaten then. If you don’t soak pellets, this can lead to constipation! Also, pre-soaked pellets tend to sink, so that your goldfish won’t gulp air, while feeding on non-soaked pellets at the surface.

Goldfish eat by taking a “bite” out of their food or by sucking it in through their mouth. They even have teeth located far back in their throats!

Goldfish are extremely sensitive to swimbladder problems. The swimbladder is the organ that is responsible for a fish’s buoyancy in the water. If you feed pellets dry, they will expand in the fish’s stomach, blocking the pneumocystic duct, so that the swimbladder cannot inflate or deflate properly. This results in goldfish that become “sinkers”, that is, they cannot rise from the bottom of the tank or “floaters”, who bob like a cork at the surface and cannot swim downward into the water or remain submerged. A type of pelleted food that is touted as causing less problems with the swimbaldder is Progold from goldfishconnection.com.

Your goldfish will love to eat vegetables! Good choices of vegetables are romaine lettuce, spinach, cucumber, shelled cooked peas, green beans, zucchini and carrots. Be sure to blanch the veggies before feeding it to your fish. Blanching is partially cooking vegetables either by steaming, parboiling or popping them in the microwave for a few seconds to kill bacteria or a minute or so, to make the veggie soft for your fish to eat. Let the food cool down before feeding it to your fish. You can purchase a vegetable clip with a suction cup, which fastens on the inside of your tank, to keep the foods under the water because they tend to float onto the water’s surface. Likewise, you can weigh them down with a rock and elastic band.

Do not feed your fish food items like ground beef or cheese, as their digestive systems are not equipped to handle such foods and they will become sick and malnourished. Goldfish are unable to digest the lactose found in dairy products. Both mammalian meats and dairy products contain a lot of fat, which may lead to a fatty liver problem.

Goldfish always act hungry and will keep eating if you let them. It is up to you to make sure that they are well fed, but not overfed! If you overfeed your goldfish, it may develop a swimbladder problem. Under such circumstances, fasting for 48-72 hours usually corrects the constipation and swimbladder problem created by overfeeding. This can then be followed by feeding peas and a gel-based food or frozen but thawed bloodworms.

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What fish can I keep in the tank with my goldfish?

It is always important to do your homework and research the compatibilities when housing different types of fish together! There are some problems that can result when keeping goldfish with other types of fish, and therefore they do best when kept in a tank with other goldfish. These problems include:

• Fin nipping/bullying – Other fish may harass the slow swimming goldfish and cause immunity problems leading to disease and death.
• Some algae eating fish, like the pleco and oto cats, will suck on your goldfish’s slime coat. At night, goldfish tend to rest near or on the bottom of the tank. Plecos are nocturnal creatures and will take this opportunity to suck the slime coat of the goldfish. This will often lead to extreme stress, infection, and/or death.
• Other fish may be eaten by your goldfish. If a tankmate can fit into your goldfish’s mouth, then it may well end up as a meal!
• Environmental Conditions – Goldfish are coldwater fish and need a specific temperature range, which is typically lower than that required of tropical fish. Likewise, other fish may have different pH, hardness, food, etc. needs.
• Goldfish need a lot of dissolved oxygen. If there are fewer fish in the tank, then there will be more oxygen for your goldfish.
• Goldfish produce massive amounts of ammonia. If there are fewer fish in the tank, then there will be less ammonia produced overall. The ammonia that goldfish produce may harm other fish, especially the more sensitive ones.

That said, white cloud minnows and dojo’s can be kept with goldfish; though keep in mind that a goldfish will eat any fish that fits into its’ mouth!

The fancy type goldfish can be kept together and the non-fancy types can be kept together. The fancy types (e.g. Oranda, Ryukin, Ranchu) and the non-fancy types (e.g. Common, Comet) of goldfish however should not be housed together. The fancies require warmer water temperatures than the non-fancies. The non-fancies are quick aggressive fish that will easily harass the fancies as well as outcompete them for food.

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One of my fish is harassing the others, what should I do?

Often, males will become aggressive and nip at the female around the tail and backside area at mating time. The males may have breeding tubercles visible (white dots near the gill plate). This is generally regarded as normal behavior.

If you have a community goldfish tank, one fish tends to be the leader with the others following it around the tank. This “alpha fish” may be more aggressive to the other fish.

If the aggression in a tank becomes too much for a fish, then you can either separate out the aggressive fish or the bullied fish into a new tank, or get a tank divider to separate the passive from the aggressive fish.

Be sure that your fish is not ‘flashing’, which means running into or bouncing off of gravel, decorations, etc., as opposed to intentionally bullying other fish. Flashing may indicate a parasitic disease or water quality problem, such as elevated ammonia or nitrites.

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Can I keep goldfish in a pond with other goldfish or other fish?

If you are keeping more than one type of fish, make sure that they are compatible. Common and Comet goldfish can be kept together with koi. Make sure that the goldfish are smaller than the koi. If the goldfish are smaller, then the koi tend to be calmer and not as aggressive. If the goldfish are larger, then the koi may attack and the koi will usually have lots of weight and speed behind it. Things generally go smoother when koi are at the top of the power structure.

Do not keep fancy goldfish in a pond with any other fish, including Commons and Comets. Koi will nip at the fins of fancy goldfish and will chase them because the fancies are slower and less aggressive. This can lead to stress, which causes a weakened immune system and paves the way for disease. Fancy goldfish also have special water temperature needs. Fancies need temperatures of 75-80ºF, where koi and comets/commons live in temperatures in the sixties. Keeping non-fancy goldfish in 75ºF+ temperatures may cause them to have rapid gill breathing and even to gasp at the surface due to a lack of oxygen.

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Why does my goldfish only float at the water’s surface &/or swim upside-down?

This is a swimbladder problem and a goldfish that floats or swims upside-down is said to have “Flipover”.

Goldfish are extremely sensitive to swimbladder problems, especially the fancy types because of the globoid shape of their stomach. The swimbladder is the organ that is responsible for a fish’s buoyancy in the water. If you feed pellets dry, they will expand in the fish’s stomach, blocking the pneumocystic duct, so that the swimbladder cannot inflate or deflate properly. This results in goldfish that become “sinkers”, that is, they cannot rise from the bottom of the tank or more commonly “floaters”, who bob like a cork at the surface and cannot swim downward in the water and remain submerged.

Swimbladder problems are most often a result of feeding dry food without soaking it first and/or from overfeeding, causing constipation. Some fish are very sensitive to even soaked food so a gel-based food could be used in this situation. A type of pelleted food that is touted as causing less problems with the swimbladder is Progold from goldfishconnection.com.

Fasting your goldfish for 2-3 days will usually resolve the constipation and swimbladder problem. If that does not work, feeding blanched (frozen) peas that have been shelled may help.

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I think there may be something wrong with my goldfish… HELP!

If you do see any abnormal outward signs on your goldfish, such as “grains of sugar” (Ich), a yellowish/goldish powdery coating (Velvet), fuzzy patches (Flexibacter), red streaks or bloody splotches (septicemia), abdominal swelling with scales sticking out (dropsy), eyes bulging out (pop-eye), a thick cloudy coating (slime coat parasites), torn, ragged fins with an eaten away appearance (fin/tail rot), problems swimming or floating (swimbladder disease), or your goldfish is not eating well, and is acting sluggish and/or is flashing (rubbing on objects in the tank), then please go to the Flippers ‘n’ Fins’ Emergency Room and post your specific problem there for treatment advice.

If your goldfish is gasping at the water’s surface, he may not have enough oxygen or he might be reacting to a poison. Perform an emergency 25% water change with conditioned, same-temperatured water and be sure that the aeration/filter in the tank is working properly. Check the parameters on the water removed from the tank. Check the water for pH, ammonia, nitrite and nitrate levels. Ammonia and nitrite should measure zero. Nitrates should be kept at 20 ppm or less by regular partial water changes. Be sure that you did not forget to add the water conditioners when you last changed the tank, which remove chlorine and/or chloramine because these chemicals are toxic to fish. Also, investigate whether someone may have sprayed a chemical near or into the tank.

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Why does my goldfish has white spots only around his gills?

These are most likely “breeding tubercules”. They will appear as a sign that the male is in his prime and ready to mate and do not indicate a problem. If, however, there are white spots all over the fish’s body, your goldfish most likely has an infection from the parasite, Ich.

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Is it ok to pet my fish?

As appealing as this may be, please restrain yourself from doing so. It is understandable that they may rub up against you once in a while as you are doing the tank maintenance, however, ‘petting’ your fish can cause problems. Just the act of handling a fish can be stressful to it and stress lowers a fish’s resistance to infection. Petting your fish may wear away or scrape off the slime-coat of the fish, taking away its’ protection and immunity, making it more susceptible to disease. You might even accidentally injure the fish more deeply by ripping or rubbing scales off. If you must handle your fish, adding some NovAqua®, PolyAqua® or Stresscoat® to the tank may aid in healing its’ slime coat.

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What hygienic procedures should I use when dealing with my goldfish tank?

Always wash your hands before you clean the tank with soap and warm water. Then, be sure to rinse them off thoroughly to ensure that you have no soap residue left on your hands, as it may be poisonous to your goldfish.

Avoid feeding your fish from your hands. This may lead to disease, for both you and your fish.

If your fish is sick with something like TB or septicemia, you should wear gloves when doing maintenance on the aquarium. These diseases may be spread to humans; fish TB in the form of fish tank granuloma and Aeromonas septicemia, may cause a gastroenteritis with nausea, vomiting and diarrhea. Do not use latex gloves that are powdered on the inside, as the powder may be harmful to the fish when it gets into the water. There are special ‘aquarium gloves’ made for this reason. If you are allergic to latex, then use powder-free gloves made out of nitrile.

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Who do we wish to thank?

A special thank you goes to Noah’s Pet Store and King Ed Pet Store for allowing us to use pictures of their beautiful goldfish! At Noah’s Pet Store in Metrotown, Alex, Susan and the kids are very helpful and knowledgable and at King Ed Pet Store on Kingsway, there is a whole basement dedicated to a wide variety of fresh and salt water inhabitants and the staff are extremely helpful! Both places are located in Burnaby BC and are dedicated to all sorts of pets… from lizards, fish, frogs and aquarium supplies to birds, and all sorts of four footed furry friends. If you are ever in the neighborhood, stop by and tell them that Flippers ‘n’ Fins sent you!

We’d also like to thank Luke and Kim for sharing their goldfish keeping knowledge, Mel for her picture of Gibbon, Koko for sharing a picture of breeding tubercles and Debbie for her pictures of flipover, so that all could be included in this FAQ!

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