Tiger Barbs are often cited as a good mate for smaller sharks. They get to be a decent size and they can be aggressive. However, the mistake most people make with Tigers is getting too few of them. In that case, the Tigers get *really* aggressive with other fish in the tank. With more Tigers, they are more preoccupied with each other and they are in a more "natural" setting that way. I'm not so sure about Tigers with Gourami though. A single Gourami is usually rather peaceful and it is a slow-moving fish, which is a disadvantage against the quick Tigers. Also, the Gourami will only be a couple inches big and the Tigers will be bigger than that. I would really research that one, but it doesn't sound like an obvious match.

Also consider that fish are generally identified as peaceful, semi-aggressive, or aggressive. It is usually best to keep peaceful fish out of a tank with semi-aggressive and aggressive fish. That is a generalization, but it is very often applicable. The more aggressive species can hold their own against each other (if size is similar). You will hear of people keeping a "semi-aggressive" or "aggressive" tank. Cichlids are an example...most are aggressive to some degree and will torment/kill more passive fish, but a cichlid species tank works.

Imagine wild animals.....you wouldn't mix a lamb with a den of lions.

Zambize

upside down catfish
and a plecotomus


oh...I have none of these fish besides the gourami and rainbowshark
these are just a list of the fish I'm looking at and really like