Well, I've kept fish longer than I've been herping, and I can tell you, that ISN'T enough. Tetras and rasboras both need large amounts of space for their size, and are lil' mess machines, like their relatives. Also, these fish are much happier in a big school, with a wide area of space, and plants only* as hides, preferably around the edges. The ottos, I've never kept, but from my experience with similar sized, similarly habited fish, it needs 5g water, and 2 sq. ft. of surface (decor don't count) BARE MINIMUM per individual. With this said, get a 29g, some live plants from the amazon, some nice driftwood (ottos will LOVE this!) and set up a tank with an oversize filter (always recomended, esp with cypranids and cichlids). Enlarge each of the tetra/rasbora schools and make a nice habitat tank. *-This includes driftwood. Better yet, get some wood with a plant growing in it.