i've tried various tips passed along on this subject, and i have found that the most important thing, is keeping the temperature down to just above freezing. it slows their metabolisms down, thus reducing oxygen requirements. i should probably pickup a pump to aerate, or move the water around, but all i do is manually dump water into the bucket and add fresh snow or ice every other day. they seem to do quite well and lose only the occasional minnow. grump