Cory fin damage

[Ramphonic]

I bought some Skunk corydoras a few weeks ago. I just noticed one has had the bottom fin ripped off. Either that or its some bad finrot.. His underside is all red and puffy. Is there anything I can do?

Hes in the tank with the other skunks, 2 Bristlenoses, and some guppies.

The substrate is pool filter sand and I have some slate in there.

[Dangerdoll]

It sound like either the substrate is too sharp for him or that your parameters are off. Have you checked your levels? When you do your maintenance on the tank, do you stir the sand at all?

Posted on mobile.aquariacentral.com

[Ramphonic]

heres the clearest pic I could get. Its not on any other fins...

[Ramphonic]

I do a 50% water change a week , Its a 20g high with a ac30 filter.. I do let the python sort the sand a little bit.. Waters 78 degrees, 5 ppm nitrate and 0 ammonia and 0 nitrite

[Dangerdoll]

yikes, that doesn't look good... it looks more like toxins than irritation though.... do you ever notice bubble rising from the sand? Are all the other fish ok?

Posted on mobile.aquariacentral.com

[Ramphonic]

no bubbles.. all the other fish are very energetic

[Ramphonic]

heres another pic

[Dangerdoll]

I have to admit, I am stumped. It's possible it could be injuries but I am not comfortable with that because of where the redness is. I am hoping someone else can weigh in.

Posted on mobile.aquariacentral.com

[BettaFishMommy]

it could be a bacterial infection that was starting to show before you got the cory. septicemia comes to mind.

[Juice]

if your params are correct than i vote for bacterial as well

[Ramphonic]

Well he was upside down jammed up next to the heater. So I put him out of his suffering. The area was very red and looked ulcered.. At first I though it was just his fin but it looks like this is more on his belly

I may have started before I got him, Ive had them for just about 3 weeks