la loser88

I was wondering if my red tail shark and tiger barbs would do well with a sword tail.

TFA101

It would have to be a male, since they are more agressive and will be able to hold their own. They are, however, prone to being nipped at the fins by your barbs, so make sure there's a return policy at the pet store your purchasing your fish at

zambize

It sounds like it might be a balancing act. Male swordtails are known to be aggressive, and I can attest to that, so it could be a less-than-peaceful tank with constant fighting, or they could all be semi-aggressive and therefore co-exist. It sounds risky to me.
Personally, I'd go with a less aggressive fish that is around the same size as the RTBS. In my research I've read that RTBS can co-exist with 1) super passive fish too big to eat (Cories), 2) equally aggressive fish, 3) or more neutral fish that are about their same size. I have an RTBS with Leopard Cories and a male Dwarf Neon Blue Gourami will soon be introduced. The Gourami is a fairly passive guy, but won't take any crap if pushed around, so I think he'll work.

Zambize