My dad has a 300 gallon mixed reef tank and we have found tons of stuff to put in the tank on the floating docks at the yacht club. We feed our fish mainly shrimp, and there's tons there. There's also brittle stars, small crabs that are good to feed the fish because of the calcium and all that goodness in the shell, anemones of different sizes and colors, muscles that I love putting in his tank, hard corals that are harmless if you don't put them next to other corals, and many other cool things. Today we found a few striped hermit crabs, and although most people don't like them, we've had some that we bought from the store that are harmless. If you want to go down to the floating docks, go to right side of the bridge. Bring a bucket and a somewhat large net, but don't go crazy about that, and try to be invisible! We haven't gotten kicked off the docks yet, but it's important to be respectful of the docks. p.s: The black spider-like things that you will probably find down there are not poisonous, but don't keep them! Other than that, I hope I helped!