My tank has finished it's cycle over a while ago, and the last week I've had some critters in there. My tank is a 55 gallon. Salinity stays at about 1.025. Tank inhabitants at the moment: 2 pepperment shrimp 1 fire shrimp 1 decorator crab 1 sea hare 1 red knobby star 2 turbo snails 2 margarita snails 5 red leg hermit crabs 2 emerald crabs 3 bumblee snails I also have some macro algae in the tank. I don't mind if the Octopus eats anything I currently have when I get it, and will remove the decorator crab as a potential threat. I've been advised this isn't by any means a sufficient bioload to maintain my bacteria population. I've been advised to add fish, but wanted to avoid this for two reasons: 1) To avoid any possibility of introducing copper in to my tank and 2) because I know they are hard to remove. I would like to know if there are any fish that I could add that would be fine with my setup at the moment, are unlikely to be treated with copper and can be easy to remove. Other suggestions in place of fish would also be welcome. I was planning to add a red brittle star, but haven't managed to find one in a LFS yet.