Yup treating g with furan and today he seem better the redness and swelling when down a littleLooks like a little redness in the anus area and where the ventral fin connects to the underside.I'm not sure what it could be though.
i net it to put it in tank as i just got him and one smaller st. a few days age took 50+ hours to get to meDid you net the fish recently? The anal fin spike is showing a bit of lost of skin tissue.
What did you feed it?
Could be parasite infection, internal blockage, or the infamous datnoid disease (usually red pimple, or bump)
thx treat him with furan 2 nowIt's a bacterial infection... Salt/ clean water/ melafix will heal it. I had a ST with the samething and that's what I did to heal it up.