Well, i bought the dragon goby to clean my sand bed and it is doing an excellent job and I don't plan on getting rid of it. The eel is not real big, maybe 10", and it gets along great with my two medium sized false percs.
I would add a bi-color angel,you have enough lr for it to graze on while it gets used to (red tetra slow sinking pellets is what I use,helps there color)and live and frozen brine..the angels stunning yellow is what you might like in there...