There is a fish which is called the tilapa. It has since been renamed St. Peter's Fish. You can find a story in the Bible about it, in Matthew 17:24-27

The tilapa carry their eggs and afterward their young in their mouths to keep them safe. The young vacate the mouth long enough for the mother to eat, but then reassume their place within it.

When the young grow large enough that the mother no longer wants them there, she will pick an object, preferably a shiny one, and keep it in her mouth to prevent the young from returning.

In the case of Matthew 17, the fish that Peter caught had picked up a shekel piece.

Tilapia is my wife's favorite fish. "According to the tale, the dark spots on the sides of the fish, a common pattern in many tilapiine cichlids, are the fingermarks of the saint." I cab't get her to eat cod because her father made her drink so much cod liver oil when she was young. She doesn't like salmon or tuna but will eat pollock.