If you get a red tail shark, beware. They are cool looking and very active fish with fun personalities.... however, once they are fully grown they will chase any other fish they see.
"Chase" might be an understatement. The shark will not rest until the other fish is gone or dead.
Had to take my RTS out of 40g community because it started to harass more and more of the fish as it matured. At first it messed w/tetras, then danios, then my tinfoil barb, then gouramis, and finally it couldn't even deal with loaches anymore.
I put the shark in a 20g-long all alone... he seemed happy but much less active... but any other fish I put with him gets terrorized. Latest experiment is a blue crayfish... just put him in yesterday.
They are both fearless... the shark tries to ram the crayfish with his nose, or block him from entering a decoration or etc.... and the crayfish just pushes the shark out of his way (thankfully without snapping off a fin in the process!)
I'm thinking the crayfish will be dangerous to the shark if this keeps up so I will probably move him out... but it seems to be the only thing that can tolerate the shark so far.
So yeah... a RTS in a 29g community tank is great when they are juvenile... but I'm told they will not tolerate any other fish in a tank short of 100g when they are full grown.