* "Black fish" is not a specific fish species. It's possible someone might use this term to refer to a dark-colored fish, but it wouldn't be scientifically accurate.
* Orcas are not fish. They are marine mammals, specifically toothed whales.
It's likely that there's been some confusion in the terms. Can you tell me more about what you're looking for? Perhaps you're thinking of a specific type of fish with a black coloration, or you're curious about orcas and their characteristics. Let me know!