Is a tuna fish cartilaginous fish?

No, tuna fish are not cartilaginous fish. They are bony fish.

Here's why:

* Cartilaginous fish have skeletons made of cartilage, a flexible tissue. Examples include sharks, rays, and skates.

* Bony fish have skeletons made of bone. This is the case for tuna, as well as most other fish species.

Tuna are a type of ray-finned fish, meaning their fins are supported by bony rays.