Mako

A shortfin mako shark mermaid, "Mako" currently lives in a research and conservation center that doubles as an aquarium. She shares a tank with her partner Maroon (a lionfish Mermaid), and has taken a motherly role towards Torrent (a small lantern shark Mer). She gets along with most of the staff, but particularly likes talking to Rocky and Minuet-- two brothers from the Attwatere family, who are themselves marine biologists and partial owners of the aquarium. 

Mers in this universe have their own language which is very musical and sing-songy, but it gives them difficulty with a lot of spoken human tongues. So most opt to learn sign language for communication, even if they can understand the words they hear.

Mako herself doesn't have much patience, and can come off short tempered at times, but she has a big heart and a lot of energy.