These are the main staple for most of my fish. They must be rinsed thoroughly, as they come from stagnent water! I use a brine shrimp net & rinse them every time before feeding. I usually buy a 1/2 cup/week for my 8 tanks. I store them in a coolwhip container with holes on top, in 1/4" of water, with a few drops of liquid vitamens. Throw away any that loook bad.