More facts, inspired by today's trip to Big Al's:
-The family relations of a fish do not have any correlation to how peaceful or aggressive it is. For example, while goldfish might get bullied by African cichlids, red tail/rainbow sharks would be the ones bullying the African cichlids.
-Perhaps unfortunately, an awful lot of tankbusters (think pangasius, red tail catfish, tiger shovelnose catfish, walking catfish, tambaqui, etc) enter the trade as aquaculture byproducts (or in other words, they and the frozen fillets of the adults in your local supermarket come from the same fish farms) instead of rigorous expeditions to the Mekong or Amazon for some expensive wild-caught exotic fish that fishkeepers worldwide will pay top dollar for.
This means that not only are they not going away anytime soon, they completely lack the prohibitive price that protects other 'not-for-small-tanks' fish?
-Breeding Siamese fighting fish is not a particularly good idea (or at least, it won't be until more people research fish before buying). Chances are, the vast majority of the fry will end up in situations like
this one.
-Yoyo loaches and Burmese loaches have trackable juvenile-adult pattern shifts that add considerably to the joy of keeping them.