Bettas, then khulis. They're pretty much the only types of fish I've kept that haven't died (OK, the only other types I've kept are guppies, tetras and corys, but they all died of various lfs linked diseases). That I haven't kept, birchirs, giant gouramis, biiig catfish such as giraffe cats, RTCs, etc, rarer L numbers (such as the zombie pleco) and a lot of other oddballs (like ABFs).