More fish?

[Joey17]

In my 30 gallon i have 1 dragon goby 2 bumble bee gobies, 1 knight goby and that's pretty much it. Anything else i can put in it? What about a green scat?

 

[penpitt]

I would guess that you are full as it is. Dragon gobys get fairly large, I think around 18 to 20" . Green scats can get up to 12" so you would definately be overstocked with the scat.