Your Strength score increases by 2, and your Constitution score increases by 1.

As a fishman you have gills alongside your lungs. You can breathe underwater as easily as you can in air, and are unaffected by ocean pressure to a much deeper point than humans.

As a fishman you are used to being underwater, making acts of athleticism much easier to perform when underwater.

A fishman's skin is naturally slippery due to their aquatic nature, making it more difficult to grapple or restrain them.

Fishmen are naturally athletic due to having to spend most of their time underwater, and swimming a lot.

You can speak, read, and write Common and Aquan