I have one in a 40 gallon reef and hes one of the funnest to watch.i got lucky because he only burrows under one rock on the side so he doesnt destroy anything. i also tried pairing a yellow watchman with it but they didnt get togehter. i think it was because the goby was sick when i bought it, poor guy died. but either way i like my pistol, cleans the sand in his area and eats up any loose food. Only downside is the clicking noise you hear all the time from there claw. if you look it up on youtube theres a really cool video showing one in the wild shooting his ''pistol''. All n all i havent had any casualties from him and i find to to be a very interesting species.