Hole in Danio’s Belly

[isaakw]

I noticed he has been swimming weird for a couple weeks. Today I saw that he has a hole on his belly. One of the danios often chases him around so Im not sure if it is an injury..

Tank is 15 gals
3 glo danios
1 female betta
4 otos

low nitrates and nitrites, no ammonia, approx 7 ph, 76 degrees

 

[Colin_T]

It appears it had a parasite inside it and that has come out through the side. If the fish is eating it might (unlikely) heal up. If it doesn't eat or the hole doesn't heal up in a day or two, euthanise the fish.

 

[isaakw]

Ah that makes me sad… He is still eating though

I didn’t think it was related, but I have seen little white worms in the substrate. I read that they are harmless detritus worms, but I may be wrong. Is there anything I should use to treat the water for parasites?

 

[Colin_T]

Small thin white worms in the substrate are detritus worms that are harmless. However, they normally live in the gravel and if they are out and about, there is a problem with the tank. It could be dirty substrate or poor water quality. Doing a 75% water change and gravel cleaning the substrate every day for a week will help get the worms back into the gravel, and it will also reduce the number of disease organisms in the tank so there is more chance of the fish healing up.

You don't use medications on detritus worms and the parasitic worm (this is what they usually are) that came out of the fish won't survive without a host so is probably dead on the bottom or in the filter.