THanks for replies. Hmm, that's an interesting point about the gravel. When the 10gall cories first got sick, I read something about UGF systems not being that great for bottom feeders, so I put them into the 37gall. Well it did cross my mind that maybe the gravel was too big & bothered their ...

Thank you Jools. And now that I have a bit more time, I can add some details. I had the 3 pandas in my 10 gallon for several months, which has the same exact stats as 37, except it's kept quite a bit warmer--around 76f. This is where they first started getting fungus. I moved them to hosp tank ...

Sorry, was in a bit of a hurry, didn't mean to offend anyone's sense of protocol...or whatever.

Hi, can't figure out what's going on with my cories, they are dropping left and right.

Tank stats:

37 US gallon, running for 7 months, weekly 30% w/c with light to heavy gravel vac

Penguin mini bio-filter
Penguin 170

Temp 72f
Ammon 0
Nitrites 0
Nitrates 5
Kh 10
Gh 12
pH 7.8

Few live, but ...