I want to bring back an old article that was temporarily removed when we updated our site earlier this year. We’ve been getting a ton of emails from readers treating their bettas for all sorts of diseases. I wanted to be sure to share this information as a warning to all our readers.

It’s original title, Dangers of Preventative Medicine was first published on November, 14, 2004.

Every day I get questions about how to medicate a sick betta. The majority of the time, the person asking has no idea what is actually wrong with their fish. In addition to that, too often they have already begun administering one or several medicines. I’m inclined to ask them,

“Would you take penicillin for a headache?”

Let’s face it; most of us wouldn’t fill our bodies with potent antibiotics or other drugs to fend off what our immune systems are made to handle naturally. When we’re sick, we see our doctor who diagnoses us and may even write us a prescription for something that will help.

Our fish are no different, except few of us have the luxury of taking our betta to a vet when they are under the weather. Instead we are forced to play doctor to them. To give them the best treatment possible, we must ask questions, make observations and determine what is causing our fish to be ill. I can spend all day talking about what to look for and how to diagnose a fish, but this article is about the importance of not overmedicating our fish. Let me say right off the bat, you do not need to medicate a healthy fish. That means, no antibiotics, no antiparasitics, no “herbal remedies” and no aquarium salt.

There are a slew of products on the market that claim to prevent bacterial infections, parasites, brighten the color of your fish and a million other things. Some of these are actual legitimate medicine for your fish but many others come in the form of fish food, water additives or preventative treatments. Some are fairly harmless but others are not. The best preventative medicine for a betta, or any fish for that matter is good clean water, vigilance and some TLC. You really never want to medicate a healthy fish and I’ll tell you why.

#1 First, medications are fairly disease specific. Some treat gram-positive bacterial infections, some treat gram-negative, some are for parasites, others are for fungus and the list goes on. Without proper diagnosis you risk treating for the wrong illness.

#2 Secondly, medications add additional and unnecessary stress to your fish. Many are quite potent and you can actually do more damage than good. Many medicines can also upset your tanks ecosystem by reducing dissolved oxygen levels and even killing off the helpful bacteria. Remember, Bettas do have their own immune systems and can often heal themselves. Save medications for only severe illnesses where the fish may need that extra help.

#3 Thirdly, introducing unnecessary antibiotics to your tank greatly increases your risk of antibiotic resistance or worse, antibiotic immunity among bacteria. Many of these dangerous bacteria are always present in our water and wait to attack fish that are stressed. Every time nasty bacteria are exposed to antibiotics they may potentially create new strains that are stronger and more deadly. An example is Flavobacterium columnare (bacteria that cause Cotton Wool Disease).
A relatively mild form of this bacteria may take a few days to actually kill your fish if left untreated, but recently more and more instances of a particularly serious strain of Flavobacterium columnare has been reported that can actually kill a betta in less than 24 hours. It is speculated that these new strains may have developed a resistance to milder antibiotics forcing fish keepers to break out the big guns (potent antibiotics) which according to #2 above adds additional stress to your fish leaving him open for even more opportunistic diseases.

#4 Finally, there is always a risk of medication intolerance or allergy. Yes, even fish can have allergic reactions to ingredients of some medications. For example, melaleuca is a common ingredient in medications like Bettafix or Melafix and has also been said to cause reactions in some bettas.

Now, I’m not saying that fish don’t ever need medicating; it’s just that certain steps should be taken first.

  • A: You should be sure (or at least have a solid guess) of the disease before medicating.
  • B: You should fix the environmental factors first. (Ammonia, nitrite, nitrate, pH, temp, etc.) After all, if poor water quality is the problem even the best medications won’t keep your fish from getting sick again.
  • C: You should allow the fish’s own immune system to heal him if the situation is not severe.
  • D: Choose the least potent drug that will still do the job and make the fish as comfortable as possible. (Increase oxygenation, lower water level, etc.)

Remember, fish aren’t all that different from us except they aren’t able to tell us when they’re hurting. To avoid illness, avoid stressors like temperature or pH fluctuations and exposure to toxins. Offer your fish a nutritious diet and clean water.

Betta splendens

Betta splendens | Photo by Phillips Jon

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Reader Interactions


  1. Angelique Harper says:

    Hello, my name is Angie.
    I am a first time betta owner, I got my boy 3 days ago from a pet shop and they keep them in little cups I was horrified!! I bought the largest fish bowl they had and a big plant with gravel. Rushed home and got him in his new house as fast as I could, I also bought a black bobble eyed gold fish so he would not be alone, they dont seem to mind each other at all, after this I started reading as much as I could on the net about my betta, in this short space of time I have fallen in love with my betta, but to me he doesn’t seem to be happy now that I know more about him I am going to get a tank, pump, and heater. I have learned that his water needs to be between 23-30 degrees. I was also thinking of getting him a girl? do you think that is a good idea or not? will they breed? I know nothing about breeding and dont want to harm either one of them!!! I just want to give him the best possible life I can. If you could help me with any of this I would really appreciate it.
    Kind Regards Angie x

    • Christie F. says:

      Hi Angie, Bettas aren’t compatible with goldfish long term. Goldfish are coldwater fish that require a large tank and strong filtration, while bettas are tropical and prefer to be alone with very little water movement. Check out our article Betta Tankmates – 7 Things You Must Consider. It is also not recommended to keep males and females together as aggression can get out of control leading to injury or death. In a large aquarium housing a male and female together may work under careful observation. For more reading, check out Large Aquariums: Housing Male Bettas with Females.

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