With the nutrition they require and a good variety as mentioned, you should see a drastic improvement.
I believe every aspect of successfuly keeping marine life involves duplicating their natural environment as closely as possible, including diet. I mean, I love Corn Pops but I don't eat it for every meal...
Deb aughta' open a catering service for the distinguished fish. Kinda' like "meals on wheels" or somethin'...
