Decisions re: 40 gallon tank

[aquakid]

This summer my ten-year-old and I started our first 20-gallon tank. It contained 3 swordtails, 6 tiny rasboras, a dwarf gourami, a lone surviving neon tetra, and a young rainbow shark.

As our community fish tank was starting to get crowded, and the rainbow shark became very territorial, chasing everyone constantly out of the bottom half of the tank, we aquired a used pair of 40-gallon tanks, one full of convict cichlids, and the other we set up with its existing gravel, filter & media, decorations, etc. and ran empty for a week. We have just moved the shark into the second 40-gallon tank and are having difficulty deciding whether to move the rest of the community fish in with him now that he will have more space, or to leave them in the 20-gallon and get some more aggressive fish such as barbs and danios to go with the shark. Moving our current fish in with the shark would mean one less tank to care for, but we are not sure that they can coexist even in a 40-gallon. Any advice would be appreciated.

[teach]

From what I have read about those sharks they are pretty territorial and cause problems until you get a very large tank. So I would go with the more aggressive fish idea. But Im just going off what I have read. Ive never owned one.

[Mvjnz]

Yeah, these fish are NOT for your ordinary community tank. They need to be kept by themselves or with equally aggressive fish.