yep, fresh stuff is great!! They like fish food for protien, and u can sprinkle calcium and vitamins on your veggies for xtra nutients. If they're not eating eachother your doing fine. I also make my own food, blend dry catfood, oatmeal, and powdered milk( just for calcium) go 50/50 and 1/4 on milk(not nessisary if u give calcium dust on your veg)

U might wana google if sudden water changes have effect on them, as I don't know. But distilled is pure h2O, no elements at all, and spinning is a sign of nurological damage, hopefully they pull out of it.