What is the type of fish that looks like a mini orca?

You're likely thinking of a black and white sea bream (also known as black sea bream, striped sea bream, zebra bream, or black-tailed emperor).

These fish have a distinctive black and white coloration that resembles a miniature orca, especially when they are young.

However, they are not closely related to orcas (which are dolphins) and are actually a type of fish in the Sparidae family.