What happens if a fish has too much air in it?

Fish don't "have air in them" in the same way humans do. They don't breathe air into their lungs. Instead, they extract oxygen from the water using gills.

Here's why too much air can be a problem for a fish:

* Air in the swim bladder: Some fish have a swim bladder, which is an air sac that helps them control buoyancy. If a fish gets too much air in its swim bladder, it can become buoyant and unable to dive properly. This is often seen with fish that are brought quickly to the surface from deep water (like when they're caught on a hook).

* Air in the blood: If a fish is exposed to air for too long, it can develop air bubbles in its blood. This is a condition called gas bubble disease. The air bubbles can block blood flow and cause damage to organs.

So, while a fish can't technically "have too much air in it" like a human, being exposed to too much air can be harmful and even fatal.