Two part post here. Not sure if this is the right section - but a mod might be able to move this to the right section.
1 - I got home today and my chromis was missing half his tail? Looked like its been chewed. He's acting normally, and swimming fine, but I'm at a loss as to how it happened! Tank mates are in my signature - and no-one's been acting agressive toward each other. Caught in the rocks maybe? I can't get a pic, but it doesnt look like fin rot or anything nasty.
2 - My sea urchin is excreting this cream powdery substance from the top, inbetween some spines. I'm thinking this is poop, but from my research, the poop is usually in pellet form. It trickles down the side of the urchin, inbetween the spines. I can tell he's eating well as he's made a dent in my coraline algae (plenty more where that came from). **edit** I looked at the anatomy of an urchin and the powder seems to be coming from it's "bottom".
Pic link below: