If you have a lot of coral, the goby might throw sand all over and cause ssome problems. My water became noticeably murkier because there was so much sand being tossed around. Also, these fish are jumpers. My water column finally cleared up one day. Found the fish shriveled up behind the tank shortly afterwards.
+1 on the sand storms at first they will cause a ruckus until they finish their complex tunnel system after that they will keep your tank bottom extra clean i had one in my 90gallon but made the mistake of not covering the top and he got into an argument with my snowflake and then he left my sand bottom hasn't been the same