@MagicJ my first lot of cardinals in the Ziss were doing fantastic, they were about a week old, happily feeding on the bbs, I have multiple batches running constantly so they always get fresh hatched. Been feed 3 times a day I leave the air off for a while so it doesn't drag the bbs out I put it on every few hours to keep the water inside clean. Then run it gently overnight while they are sleeping then add fresh feed first thing in the morning.. I wake up today to find every one of them dead on the bottom of the tumbler. From free swimming and feeding last night to all dead this morning. Not sure what went wrong. Any advice??