need assistance with fish feeding

[dreamon7]

I am starting to think it's stress rather than a problem with the food. I mean, I've had cardinal for a bit now and he was eating fine, but then something spooked him and now he's just not the same. I did vacuum the sand the other day and maybe that's what did it. I don't know, I'm just really confused and I don't want to lose any more fish.

[Orizon1]

I've had luck with adding garlic to their food, seems to get them interested, especially with the Mysis.

He's gone now. This morning, I found him on the gravel, still breathing, but I thought he was a goner at first. Then I saw him move, he swam to the other side of the tank, made a big dash for the surface but didn't make it. I'm guessing stress got to him. He started hiding and lost his appetite after I vacuumed the sand.

[olivena]

You might want to look into how the cardinal was caught, maybe it was cyanide fishing, and get some info from your LFS about where the fish came from.

What kind of water tests are you running? You mentioned nitrate, nitrite, ammonia, and pH, but are you checking for anything else? Has the temperature gone up, and is all your filtration working correctly?

Also, are you adding any trace elements?