I have a brown barred sleeper goby that has survived 3 tank moves and a crash that killed everything else in a minutes. He seems to be bulletproof. If you were near Baton Rouge you could have him, he was in a FOWLR but it soon became a reef and he seems to enjoy covering my coral in sand. I personally do not like engineer gobies due to their tunnel networks which can undermine LR and they get quite large.