Flying Locathah (5e Race Variant)
From D&D Wiki
Flying locathah live offshore, in deeper, colder waters around the rims of the seas north. They are former slaves, as most locathah are, from other creatures of the deep. It is said these locathah were granted a wish which gave them greater ability to escape the water. Where? To the air. They have great big fins that fan out like wings. While this is not entirely true, unbridled flight for the most part, they seem happy with what they've got. But there is a lot of speculation as to what granted their wish, and to what end.
This variant replaces the Leviathan Will trait.
Fishy Flight. You have large fins that can propel and keep you aloft. You have a flying speed of 20 feet, but you cannot fly higher than 20 feet with this speed.