Hi Everyone,
You probably can't help much but I have a problem and I am worried about losing any more of my fishies. I had posted that one of my coral platys had died, followed not long after by another, (Friday night).
I took his little body out and did a water change. I did test the water first and everything seemed ok, but I wanted to do one anyway just to keep the nitrates really low for my pandas and peppers.
Last night, I noticed one of my guppies (one of my first fish) resting on the bottom of the tank with his fins quite clamped to him. He roused himself for his supper but to be honest, I braced myself for the worst this morning. Unfortunately, I was right. This morning he was dead...no marks of any kind on him. The only thing that sets him apart from the rest, is that he is the one that gets harassed by one of the others.
Later today, I noticed that one of the other guppies (I only have 3 left at this stage) was doing the same thing...just laying on the bottom. I tested the water again and it seemed fine but I did a small change ...don't really know why, the need to do something, I suppose. Anyway, he seemed much improved and has been swimming around with the others and eaten.
Well now he is back on the bottom, fins clamped again, so I fear a repeat discovery. I can see nothing wrong with his scales or signs of injury. The only thing I did notice before....and I'm sure it has been the same with all the fish that I went on to lose, was that their eyes seem to go very black.
Any suggestions would be very welcome, I couldn't bear it if I lost the whole tank

Thank you,
Resa