The tropical fish are sea creatures living in the ocean. They cannot speak. In "Into the Deep", mermaids Uniqua and Tasha come across a fish swimming by their garden and recognize it as an intruder. After telling it to leave, they use the "Mermaid Freak-Out" to blow it away.
The tropical fish are yellow with gray-black stripes. They have long dorsal fins on their heads and large eyes.