I don’t want my pincushion urchin to get hungry but I also don’t want to over feed and I’m not sure quite how to tell. My current tank is 25 gallons, and is 7 months old there is a little algae on rocks and glass but not too much so I figured I’d have to supplement. I added my urchin last week and I feel like she’s gone through a lot of Nori, but I suppose I don’t have a frame of reference for how much she should be eating. This pic she has a shell wrapped in nori that she picks up off the floor of the tank and brings to the top to eat. I don’t think she liked sharing with the hermit crab. How much do your urchins eat?