I’m asking this same question in the Zoology Section of Science & Mathematics.
I’ve heard of fish hybrids; striped bass (Morone saxatilis) and white bass (Morone chrysops). I know they do it at the hatcheries. How about different species? Let’s say a bluegill sunfish (Lepomis macrochirus) and a redear sunfish (Lepomis microlophus)? Or a bluegill sunfish and a black crappie (Pomoxis nigromaculatus)? Or a largemouth bass (Micropterus salmoides) and a smallmouth bass (Micropterus dolomieui)?
How about an Oscar (Astronotus ocellatus) and the Red-Bellied Piranha (Pygocentrus nattereri)? Would this combonation be possible at all? How?
In a laboratory or hatchery perhaps.
I’ve heard of people making offspring of lions and tigers mixed, why would this not be possible with fish of relatively similar characteristics?
Also I could care less whether or not they were sterile hybrids.