New tank old fish

[Joel29]

Hello all! forgive my lack of lingo. Just got over a bought of fungal infection that claimed three fish (2 cat, one silver dollar). 1 week later and it seems to have cleared up using BINOX and RIDICH upon recommendation of my local supplier. My question is My African brown knife seems to have some sort of abbrassion oh his hind side (right side) . I netted him for closer inspection and could not figure it out. can anyone tell me what it is what caused it or give insight to ant other enamales specific to the scales of these fish either as a result of age or other reation. His tank mates consist of a needle fish , tricolor shark, plecotomas, glass fish, and bammboo shrimp . all live in harmony even after nightfall. thanks in advance!

[Tooch]

I'm not sure about what it could be, but if I'm not mistaken, knife fish are considered "scaleless fish". i.e. Like a lot of catfish, they have a more velvet texture than actual scales.

[Tooch]

BTW I just noticed. Welcome to the site!

[Dave66]

Hello all! forgive my lack of lingo. Just got over a bought of fungal infection that claimed three fish (2 cat, one silver dollar). 1 week later and it seems to have cleared up using BINOX and RIDICH upon recommendation of my local supplier. My question is My African brown knife seems to have some sort of abbrassion oh his hind side (right side) . I netted him for closer inspection and could not figure it out. can anyone tell me what it is what caused it or give insight to ant other enamales specific to the scales of these fish either as a result of age or other reation. His tank mates consist of a needle fish , tricolor shark, plecotomas, glass fish, and bammboo shrimp . all live in harmony even after nightfall. thanks in advance!

Joel,
What is on the knifefish is a burn from the medications you used. I don't know if you have a quarantine/hospital tank set up, but you should. NEVER treat the whole tank with medications, as you'll screw up the biobed, and stress the healthy fish until they, too, have problems, like your knifefish does right know. If he's otherwise healthy he'll heal, but you've learned a lesson; never treat the whole tank. Move the infected fish to a quarantine/hospital tank for treatment.
As an aside, your fish got fungus because their slime coats were compromised, either by abrasion or water quality. If water quality is up to snuff, handling with a too-coarse net probably was the culprit.
Your 'harmony' won't last forever. Knifefish are predatory, and crustaceans like your bamboo shrimp are on its natural menu. The Xenatodon is also a predator, though of the lurking and lunge style. That tank is a time bomb waiting to happen.

Dave