What do tang fish eat?

It's not entirely clear what you mean by "tang fish." There are a few possibilities:

* Surgeonfish (Acanthuridae): These are often called "tangs," and they are a family of colorful fish known for their sharp, scalpel-like spines on their tails. They are herbivores and primarily eat algae.

* "Tang" as a generic term: Some people might use "tang" as a more general term for any colorful reef fish, but that's not a specific scientific term.

So, if you're talking about surgeonfish, they primarily eat algae. This includes:

* Macroalgae: Larger seaweeds like kelp, ulva, and caulerpa.

* Microalgae: Tiny algae that grow on rocks and coral.

* Diatoms: Single-celled algae that are important for reef health.

Important note: In aquariums, tangs can sometimes be picky eaters, and it's important to provide them with a variety of algae-based foods to ensure they get all the nutrients they need.

If you can provide more context about the specific fish you're asking about, I can give you a more precise answer!