The Caribbean Sea and adjacent waters, including Florida and the Gulf of Mexico
Order Labriformes (wrasses and relatives), Family Pomacentridae (damselfishes and anemonefishes)
The threespot damselfish lives on coral reefs in the Caribbean Sea and its adjacent waters (Florida and the Gulf of Mexico). The origin of the common name is clear, with individuals having a series of spots on the body and just in front of the tail fin that fade or darken at different stages throughout their lives. Juveniles are bright yellow and may be covered in tiny blue dots (in addition to their “spots”), while adults are generally a drab, greenish brown color.
Like many species of damselfishes in the Caribbean and around the world, threespot damselfish are herbivores that cultivate a garden of their preferred algae. They carefully remove other algae and small invertebrates in order to encourage growth of their favorite species. The gardens serve two functions: 1) they provide a food source for the adult threespot damsels; and 2) they provide an area for females to spawn their eggs. Unlike many species of reef fishes that broadcast their eggs into the water above the reef, damselfishes stick their eggs to the reef surface and guard them until they hatch. Males try to keep the highest quality gardens in order to have a greater chance at success in courting a female. Once a female decides to spawn her eggs in a male’s territory, she sticks them to the algal fronds growing in his garden, and he immediately fertilizes them. Together, they aggressively defend the eggs from wrasses and other foraging predators that would love an easy meal of yolky fish eggs. Unlike in the closely related wrasses and parrotfishes, damselfishes do not change sex. They are born male or female and remain that way for their entire lives.
As juveniles and adults, threespot damselfish are eaten by groupers, snappers, and other large bony fishes that patrol coral reefs. They are not, however, eaten by people and are only rarely captured for display in public and private aquaria. Though the conservation status of this species is unknown, it is likely not at any risk of extinction at this time. However, with expected negative changes to reef health throughout the Caribbean in the coming decades, it is important to continue to monitor threespot damselfish and other species that rely on reefs as their primary habitat.