Do you have a destructive diamond goby? Heres my solution. I have a 75 gallon tank with alot of live rock. My first fish was a diamond goby. He became possessive over the sandbed. I thought he was great.. keeping my sand all clean and free of algae. He is also very entertaining. He rearranges my sandscape everyday and i rake it back smooth again every evening. But now that i have decided to add corals, he is a monster! All of those same behaviors have become a nightmare. He digs under every rock until it sinks to the bottom, then he tosses sand over the top. Anyways.... after alot of frustration and a bunch of new coral frags on the way, i have finally come up with a solution that i just had to share. I basically pulled out every rock that wasnt my main structure and glued rubble rock on each, adding legs basically. So now , even if he digs them out, they will never sink below sand level. It has been about a week and so far so good. He seems to not even really bother the ones i added legs to. Only the ones sitting on the sand. So now i can put my faster growing frags on my smaller rocks! Yes! I am so happy i found a solution and still get clean sand and didnt have to rehome my fish. Here are some pictures. One, shows what he does to rocks on the sand, tossing sand on top., and the others are my rocks on legs. He just swims right past them. Now i just have to figure out how to get him to stop digging out the hole my tiny dracula goby and candycane shrimp pair all three live in! Haha.