Deteriorated Tails

My otherwise-healthy-looking cories seem to have some tail deterioration. I've included a picture, but it's a little blurry. Basically, 4 of the 5 have some splits or missing parts. Doesn't look irritated, red, or anything out of the ordinary. Water stats are good-- zero ammonia and nitrite, and nirtate is low (don't have the exact number). I do water changes at least once a week, sometimes more but only because I want to keep the sand clean. Any thoughts? Thanks!

-P

(Note on the pics: The tail of the fish on the right looks worse than it is. Focus on the top half; the bottom half looks like it's practically gone in the pic, but it's just the angle. The tail of the fish on the left shows how the bottom half is asymmetrical compared to the top.)

Edit for pic size

i would treat
with an anti fungus and fin treatment

drewry said:

i would treat
with an anti fungus and fin rot treatment

Click to expand...

Thanks! Wouldn't the fins be showing other signs if it was fungal?

-P

I know your water stats look fine but this is usually a sign of bad water quality. Do you do a weekly vac and water change? I would do a few water changes with really thorough vacs - move all your decor and dig down to get as much gunk out as possible and treat with meds as advised.

If your certain they arnt being nipped by other fish, I would treat with meds and do a water change to be on the safe side