Unexplained Deaths

[Lilly Marie]

So glad I signed up for this site. You're all extremely helpful! I, unfortunately, need your help again.

Two days ago I came come to find my smallest angelfish (4cms from Dorsal to Ventral fin) floating under a plant. At first glance I thought she was dead but when I moved the plant she started swimming in spirals and floated around the floor. She was taking slow breaths and then would suddenly take large gulps of air and continue to breathe slowly. Tried feeding her mashed peas but she wasn't hungry and about two hours later she died. Physically, she looked healthy and normal.

Today I came home and fed the remaining Angels (3) their frozen bloodworms and after they'd eaten I noticed that they all huddled in one corner of the tank (10G), which is weird for them. I had a look around for my sucker fish and found it on the other side of the tank, dead, with white flaky stuff growing on his head, and areas of his gills/head/stomach were redder than normal.

One of the remaining Angels is breathing fast (Stress?) but otherwise acting normal and the others seem perfectly fine. What's going on? The filter works, there's enough aeration, the water's fine, the temps fine, the plants are all in good condition and I'm doing normal water changes. There were no signs that the deceased fish had anything wrong with them until a few hours before they died. No spots on them or bite marks.

I'll be moving the Angels into a new 45G tank once it's cycled, I'm just hoping they make it until then ):

[Lady Hobbs]

Water parmeters? We need ammonia/nitrites/nitrates to give an informed opinion here. If you had a dead, rotting fish in your tank, you probably have an ammonia spike.

Always do a large water change when in doubt. To say temps are fine, filter is fine and parmeters are fine tell us nothing, really.