hmm, stocking info?

Well, i was thinking about what i should do with my 20 and 10 gallon tanks, since they are both empty, i was maybe thinking of creating a goldfish community in the 20 gallon, and a habitat for a crayfish in the other, but i want to hear what you guys think, i was also wondering about bettas

i was thinking more about not ACUAL goldfish, but ones that fit in the category of goldfish community, such as dojo loaches, those guys are neat