dragon gobies would out grow a 55gl me personally, i think they need at least 75gl as they can reach over 12in. I've seen most top out at 16-18in. and like most gobies they are rather lazy same with the "freshwater" snowflake eel (gymnothorax tile) but i have seen them more than 20-24in. i have even seen some at 30in. but they should do just 75gl but the eel will eat the bumble bee gobies but someone correct me if i'm wrong