Any advice for combatting fin rot in a betta fish?

They sell antibiotics in most fish stores to treat it. I think it’s bacteria that cause the problem.

Make sure your water conditions are okay. Water that is too acid or too basic can literally eat away at the fins. Have the local pet store test your water conditions.

I’m not sure that exclusively feeding freeze dried blood worms is a good idea. I’d mix it up with a prepared diet. And I typically feed my bettas small amounts twice a day. I don’t profess to be a betta expert, but the shortest life-span I’ve had was 7 years, so they seem to be thriving.

Yes, the antibiotics they sell work well. Also, use a good spring water when doing the water change. I had a betta live 7yrs and I fed him daily. He liked the blood worms and the betta pellets. All of my goldfish live long lives.

I use this water conditioner regularly with all of my fish and use a liquid barley and an algae control as needed.

The fin won’t grow back, but it should be healed with treatment, if it is sore.

In the short term as @Adirondackwannabe said there are medications you can get at most fish stores. Do not mix the medications, and since its one fish in I assume a bowl (or some small tank) do not use much of any medication. Too much and you can put the fish into shock, especially if it is already weak.

You need to change the water fairly regularly. If you keep up on it you don’t have to clean all the water, maybe ⅓ a week or every other week. They sell chemicals you can add to the tank after adding new water (or to the water before adding to the tank preferably) that immediately remove any chlorine or other contaminants in drinking water.

For your current fish since he is in bad shape I would recommend preparing the new water by letting it sit out, uncovered (as much surface area as possible) overnight. This will remove most the contaminants (and adding a small amount of the chemicals may help).

Also keep in mind that one fish does not need much food, especially a betta. You could easily get away with feeding him 2–3 times a week and barely a pinch each time.

Excellent advice from syz, but what else would we expect. Fin rot can also be a sign that the fish aren’t in optimal health. Really healthy fish aren’t as susceptible to problems.

I use Poland Spring, because I read that the ph of Poland Spring is as close to optimal as you can get.

@jca Good! I use the same brand with each water change. That way the fish don’t have to adjust to the variances of my well water.

Do you add any conditioners? If not, you may want to start. I have found that prevention is the key to happy, healthy fish. Did the water get too warm recently? Possibly this caused the ammonia build up. Otherwise not doing a partial water change soon enough may have been the culprit. I found for my betta that vacuuming every other week and doing a partial (20–30%) water change prevented most issues.

I use Triple Sulfa. My fish had Hemorrhagic Septicemia, which it treats, as well as, Mouth Fungus, Body Slime and Eye Cloud, Bacterial Gill Disease, and Fin Rot. It works really well. After a few carefully measured out doses, my fish was back to being healthy and happy. I definitely recommend it.

Today I bought some anti-bacterial stuff at the pet store. I poured out the majority of his water. I see that the heater is covered with green slime. Not sure what it is, but I removed the heater from the tank, cleaned the filter, and replaced most of his water with new Poland Spring. Tomorrow I’ll start using the anti-bacterial stuff. No heater for him now, it’s warm enough. I got the heater in the dead of winter, when I was feeling sorry for his tropical self, living here where it’s cold.

Ahhh @jca do you have a temperature strip on the tank? I only use a heater as needed which at my home means mid-autumn through mid-spring.

The slime is most likely algae. You may want to do some light algae-rid at each water change.