Shelbi with Fin Rot. Image provided by BS
Q: BS wrote,

My betta fish Shelbi has fin rot now. His water is and has been pristine with the parameters at their perfect spots. He had blackened tips when I bought him but I thought it was just his coloring. Now his fin tips are damaged and broken. I did water changes and checked his water repeatedly before getting medications to see if he could heal himself but he just got worse and I didn’t want to waste time while his tail dissolved away. I kept him in unmedicated, clean water for a month and a half. When it just kept getting worse, I went to the pet store and bought T.C. Tetracycline and Maracyn-Two. My other fish, Ember had gotten fin rot now, too because I didn’t have another tank to separate him from Shelbi. Ember cleared up almost immediately and I bought a hospital tank for Shelbi. Shelbi has gone through two Tetracycline treatments to no avail. I started Maracyn-Two yesterday and no improvement yet. What else can I do? I have attached a couple pictures of his fin rot. Will his tail grow back the same as it was? Right now it looks very tattered and short and the fin rot is progressing, fast. How long does it take to grow back and regain color?

Also, I went out of town for a week and when I came back, Shelbi had a white speck on him. (it’s actually not really white, it’s kind of gray). It’s not protruding or clumpy or anything, just a white speck, so I don’t think it’s ich. I have also attached a picture of it. What do you think it is?

Poor Shelbi has had a rough time lately, I am trying to do my best to take care of him!

His hospital tank is:
-10 gallons
-heated to 79 degrees
-medium sized gravel
-silk plants and cave
-I clean it once a week
-all perimeters are right

Thank you so much for all of the help you have given me with Ember and Shelbi. It has been so great to have someone like you to go to with questions for a reliable answer.

A: Wow, that Shelbi is one beautiful fish. I just love his color.

Fin rot, while not typically life threatening, is still a very tricky illness because it can take a long time to overcome. Torn fins or fins that have been nipped by another fish tend to regrow quickly once the problem has been addressed. Usually within a few days new tissue growth can be seen and significant regrowth can be observed within a few weeks. Fin rot, however, is different as it is characterized as fin tissue loss due to a bacterial infection. It is not uncommon for the regrowth to be much slower or for multiple relapses to occur once new tissue has begun to take hold. Some betta keepers battle fin rot for months before they get a good handle on it.

When the fins do regrow, you may notice some slight differences in color (usually minor) or you could see a curling of the rays, especially in crowntails. This curl is usually permanent and while it may not win any awards for your fish, it will not affect him in any other way.

Fortunately, based on your photos, Shelbi’s fin rot is very minor and your hospital tank set up seems like a good healing environment. You may find, once he is finished with this course of antibiotics, that you can continue to monitor him in his usual aquarium.

Things to watch out for while he is mending:
1. Any ammonia or nitrite in the water
2. Fluctuating pH
3. Organic debris collecting where the fish may drag his tail
4. Water that is too cool or fluctuates greatly
5. Tank décor or other fish that may tear his fragile fins

If you find that his fin rot continues to worsen you may need to dig a little deeper into the cause. For example, how is your tap water treated? Are you using a water conditioner that neutralizes chloramines and heavy metals as well as chlorine? Are there other stressors that could be creating a hazard? What is your pH level from the tap as well as in the aquarium? If it is fluctuating, have you tested your carbonate hardness (KH)? It might be that we just need to take a closer look at some of the other water parameters.

You can always email me the results of your water tests and I can look them over too to see if there is anything unusual or missing from your test regimen. Let us know how he is doing. Hopefully he is responding to the Maracyn-Two treatment.

The white spec is another story. It is really difficult for me to see what is going on there. It could be the early signs of a fungus-looking bacterial infection or an actual fungus. I did see a case recently where the betta was loosing pigment and his scales around his head were turning white (not raised or fuzzy). It wasn’t anything I had seen before but would be curious if you think it is the same thing. Does it look like the scales themselves are changing color or falling out?


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Reader Interactions


  1. Peter says:

    male betta fish carewow… find it interesting… hope it’ll be beneficial for me and my friends…

  2. Mich says:

    my betta, Nicoli, has fin-rot. His tail is in tatters; he’s a halfmoon, so it’s very noticable that his tail is smaller. He developed white spots on his lips and holes in his dorsal fin. Did you cure your guys fin-rot? I’ve had Nicoli on meta-fix since i got him(he was for valentine’s day from my bf).

  3. Anonymous says:

    I just got a betta fish, and it lives in like a fish bowl (parents dont think i need a filter,etc.) and it has like whiteish spots on its head, it has the redish gills and then its tail/fin is sometimes clumped, and i have nooo clue what it is. I clean the water often and i use this like conditioning stuff in the water too.

  4. Saf says:

    So if you have organic debris collecting where the fish may drag is there any way to lessen that or remove it from fins?

    • Christie F. says:

      Organic debris can be removed from the bottom of your tank using an aquarium water siphon. If you have a very small bare-bottom betta bowl you can even use a turkey baster to remove the organic material.

  5. Carolyn says:

    Hi there. I have a beautiful, active betta, who is acting just fine and eating like a pig…but I have a problem! He has some cottony white tendrils hanging off the tips of his bottom fin. I’ve tried BettaFix, as well as a fungal cure (with malachite green), but there doesn’t appear to be any change. I keep his tank (15 litres, about 3 or 4 gallons?) clean, I have a heater to keep the water temperature constant (this is a new addition to the tank & I’m hoping the temperature regulation helps). I’m currently going to do a full water change, add aquarium salts and some Betta Fix…is there anything else I should be doing? Thanks.

  6. Randy says:

    I have three bettas with fin rot. My husband has been using melafix. Is this enough?

    • Lugia says:

      I don’t know if melafix is enough if the amount of water is under 2.5 gallons. Betta fish require 2.5 gallons of water with a heater and a filter, preferably they thrive in 10 gallons of water the best. These things are great to upgrade towards if you haven’t already to up the quality of the lifespan and health and happiness of betta fish. is a great information forum with tons of information regarding this topic and lots more stuff to look through! 🙂

  7. Hi I love your website, and have been using it ever since getting my most recent betta about 6 months ago. He is somehow losing scales on his head. I have been looking online, trying to see if this is a symtom of something. All i got was that it was from stress…? Please, please help this guy I’d be devastated if anything happens to him. Thank you so much!
    -Pedro Napoleon Dynamite (my bettas name haha)

    • Lugia says:

      Betta fish require 2.5 gallons of water with a heater and a filter, preferably they thrive in 10 gallons of water the best. These things are great to upgrade towards if you haven’t already to up the quality of the lifespan and health and happiness of betta fish. is a great information forum with tons of information regarding this topic and lots more stuff to look through to keep him happy and healthy and live awesome!

  8. Daniel Xiong says:

    Hey I’m a betta collector and I have a halfmoon double tail betta with fin rot. At first his fins were very long and perfect, he was very dark blue with white outline on his tail looked very good, made all my friends envious (they are also betta collectors.) but now that he’s like this don’t really know what to do, and I’ve had him for almost 6 months I’ve tried that bettafix for a week but just got worse and now he won’t eat and he just swims near the top his back kinda breaks the surface what should I do or try?

    • Lugia says:

      Betta fish require 2.5 gallons of water with a heater and a filter, preferably they thrive in 10 gallons of water the best. These things are great to upgrade towards if you haven’t already to up the quality of the lifespan and health and happiness of betta fish. is a great information forum with tons of information that can help you more than I can!

  9. Jessica says:

    I am a new Betta owner, and proud of it. I work in a office building and I acquired Trebek from a departing colleague. Trebek, was once a beautiful blue Betta that has officially lost his fins. This was happening before I was Trebek’s caretaker but I was wondering, canyou treat a Betta with Tail Rot while in the same tank with another Betta? Will the medication harm the healthy fish? They are separated but share the same water which is now much healthier and homier than their original owners set-up 🙂 I’ve actually grown quite fond of Betta’s and they are our Sales Team Mascots, please let me know if I can treat them together. Thanks so much!

  10. Kal says:

    You shouldn’t really house a sick fish with any unsick fish. A hospital or quarantine tank should be used. No sense in getting that sickness in the rest of your tank.

  11. Gemma says:

    Christie, please help!
    My younger sister’s Veil Tail male betta, Blueberry, is in trouble, and I don’t know what to do. We went on a thanksgiving vacation in November, and had our housekeeper feed our bettas. (I also have a Plakat male who is doing fine.) When we got back, I found that the water temperature was below 60 degrees, cloudy, and Blueberry had cotton wool disease. I immediately did a full water change for both fish, and my Plakat went completely back to normal. Blueberry, however, was still lethargic and pale. We treated him with Melafix (I understand there are risks, but we were desperate and we don’t have any good fish stores nearby.) His cotton wool began to go away, but very slowly. Next, we tried Pimafix, and it worked within two days. We did a full water change, and Blueberry was fine. Recently, his cotton wool came back, and he also developed fin rot. I put him in a hospital tank, and began treating him with both Melafix and Pimafix. I am watching him carefully, removing feces, uneaten food, and any rotten fins that fall off of his body. His cotton wool is better, but now his tail fins are blackened and his ventrals have turned into long, thin, practically invisible stringy things. Please help!

  12. Christopher G Aslett says:

    You can easily knockout nitrifying bacteria in your filter with antibiotics. Not all nitrifyers are nitrosomonas and nitrobacter so normally approved antibiotics can still cause Havok. It depends on what type of bacterial mix you have. If you knock-out your nitrifyers, then you’d get spikes of ammonia and persistent pulses of nitrite. If you don’t test at the right time, you won’t detect them. A test is only a snap-shot and not indicative of an environment in flux. Also, temperature stability is very important for ornamental Bettas. Top-up water should be the same temperature as the aquarium.

    Hospital tanks are okay as long they have permanent residents to keep the nitrifyers there. A new or fallow aquarium has no filtration and once again you’ll get spikes of ammonia and nitrite. Make sure your top-up water has no chloramine in. Just using tap safe is not enough to ensure that. I use R/O then add hardness back in. You could use a Britta filter to remove chloramine.

    Detritus is very important to remove. I run my tanks with no substrate. Freshwater fish are more susceptible to nitrate so make sure your levels are less than 40ppm. Better still half that. Bettas are normally kept in small aquariums where the environment is not very stable. This causes stress that can lead to disease. I do run with a tiny amount of salt (marine salt). I’ve tried not doing and I’ve lost very lovely fish due to the problem you’re having. They are not that hardy at all nowadays and need constant care to be right so don’t be down about it, it’s a hard job despite what people write…
    Good luck

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