So I have peppermint shrimp now for the aptasia but have been wondering why I only see 1 at night. It then occurred to me that the I have the ceramic rock on 1"X1" starboard spacers that are 1/4" thick to get flow and lots of the critters like to live under that. Including my green brittle star. It would be easy pickings for his thick arms to wrap around shrimp under the rock - after lights out I noticed he has a very full disk so I think he has been snacking! Time for sump duty. Out of water I measured his body at over 2" and total size of over 15".