20 gal stocking

The dwarf puffers aren't really good for community fish, they are very nippy towards other fish, and especially towards each other.. Betas and dwarf gourami's i'm not too experiences with, but i know both can be pretty aggressive, so maybe someone else knows about keeping them together., also if you wanted to stick with an Asian theme, perhaps you could get a small school of dwarf chain loaches instead of cories? I havn't kept those either, but since all the rest are from E / SE Asia (except mountain minnows from further north), it might be neat to have all the fish from one region. Gourami's are a lot of fun though, one of my first fish was a really cool (but mean) paradise fish.

goodluck!

Generally you shouldn't keep Bettas and gourami's together. They belong to the same family and will be very aggressive towards each other. Betta's tend to look at gourami's and Paradise fish the same way the look at other betta's...

Even two gourami will fight each other, though usually not visciously, but it depends on the individual fish. If you don't want to deal with their constant territorial disputes you might want to stick with just one. If you do go with two, make sure the tank has lots of plants, either real or fake, so they aren't constantly in each others line of sight. They also use the plants and decorations as markers, to figure out where their territories begin and end.

Also I agree with the previous poster about puffers. They don't 'look' like trouble, but they have beaks. They can do 'alot' of damage to the fins of the other fish in the tank very quickly.

labyrinth fish (gourami's and bettas) are fine together as long as they are different species, two dwarf gourami's might fight, but not a gourami and a betta, so all the species you have are fine, EXCEPT for the puffers, they'll tear everything else and each other to pieces, i'd subsititute maybe 2 or 3 german blue rams for the puffers, and you'd have a great tank

rams are extremely peaceful, the only time they show any aggression is when they spawn so as long as you're not breeding them...

i would put in 6 DPs they are so awesome