Triton

Triton Society
Tritons are haughty, rude, and secretive. Its true that Triton are a bit different from their land dwelling neighbors but they would have it no other way. In Troshon there is no people finer than the Triton and that is a widely accepted fact those who believe even one race is their equal are heavily ridiculed and someone who believed that all races are equal would probably be institutionalized if they ever spoke on this. The irony is that because they believe all others inferior, they refuse to learn from other races putting them at a bit of a technological disadvantage. But there's nothing stronger than the conviction and word of a Triton and if you manage to befriend one of these elusive creatures you have a friend for life. The Triton may be hard headed but they are fierce warriors of justice they will help anyone they see in need, even a Water Genasi.

Triton Traits
Ability Score Increase: Your Strength, Constitution, and Charisma scores each increase by 1.

Age: Tritons reach maturity around age 15 and can live up to 200 years.

Size: Tritons are slightly shorter than genasi, averaging about 5 feet tall. Your size is Medium.

Speed: Your base walking speed is 30 feet, and you have a swimming speed of 30 feet.

Languages: You can speak, read, and write Common and Aquin.

Control Air and Water:  A child of the sea, you can call on the magic of elemental air and water. You can cast fog cloud* with this trait. Starting at 3rd level, you can cast gust of wind* with it, and starting at 5th level, you can also cast wall of water* with it (see the spell at the bottom). Once you cast a spell with this trait, you can't do so again until you finish a long rest. Charisma is your spellcasting ability for these spells.

Emissary of the sea:  Aquatic beasts have an extraordinary affinity with your people. You can communicate simple ideas with beasts that can breathe water. They can understand the meaning of your words, though you have no special ability to understand them in return.

Guardian of the Depths:  Adapted to even the most extreme ocean depths, you have resistance to cold damage, and you ignore any of the drawbacks caused by a deep, underwater environment.

Names:Triton names can be found in Volo's Guide to Monsters on page 117, however, they are just vaguely sea based names so get creative.

As a player you can choose how fish like your character looks all triton have gills, webbed fingers and toes, and must have arms and legs but you could have fins on your arms, have a gaping mouth like a fish or have colored skin/scales. Its possible however that you have very few fish like traits in that case you must choose at least one and your triton could pass as a water genasi.