I've kept gobies with my Erectus for a couple years now. a Yashia w/ shrimp, a Wheeler's goby w/shrimp, Eviotas, Trimmas, Clown gobies, Priolepis, Coryphopterus, Catalinas, etc. The Zebra Catalinas do better, I think, because they range farther south. I've never once had a problem with the smaller gobies being aggressive toward my SH. and my tank temp goes down to about 66 degrees in winter and I see no ill effects.