Can a large mouth bass mate with a crappie fish?

Technically, the question you wanted to ask is "can a large mouth bass produce offspring with a crappie?" "Mating" and "reproduction" are not synonymous. For example, a dog will "mate" (i.e, have sex with) with just about any animal that will have him. Similarly, a large mouth bass could technically "mate" (have sex with) a crappie in that the bass could spread his milk (sperm) over crappie eggs. However, only two animals of the same genus will produce offspring when they mate. The large mouth bass's genus and species is Micropterus salmoides. The white crappie is genus and species Pomoxis annularis. The black crappie is genus and species Pomoxis nigromaculatus. There are others, but you get the drift. The two types of fish are completely different genus and species. Thus, the answer to your real question is no, the sperm from the bass would not fertilize the crappies eggs.