now this is from what i have read, and experinced but everyone is different, shrimp gobies are good and little,a single fire fish should be ok, they fight others,and crabs and shrimp are fine, now the books say a fire fish (dart fish) should have a 30 gallon but a 24 should be fine, also they are jumpers...now pipe fish do get long, 8inches or bigger depending on the size. just Google the kind you want and it will tell you all you need to know, i wont add them all at once. hth