The Bermuda killifish is a small fish

Fish

Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...

 which is endemic to the islands of Bermuda

Bermuda

Bermuda is a British overseas territory in the North Atlantic Ocean. Located off the east coast of the United States, its nearest landmass is Cape Hatteras, North Carolina, about to the west-northwest. It is about south of Halifax, Nova Scotia, Canada, and northeast of Miami, Florida...

 in the western Atlantic Ocean

Atlantic Ocean

The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...

. It belongs to the genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Fundulus

Fundulus

Fundulus is a genus of ray-finned fishes in the superfamily Funduloidea, family Fundulidae . They belong to the order of toothcarps , and therein the large suborder Cyprinodontoidei...

in the Fundulidae

Fundulidae

Fundulidae is the family of topminnows and North American killifishes. The 46 species are native to North America as far south as Yucatan, and to the islands of Bermuda and Cuba, occurring in both freshwater and marine environments....

 family of killifish

Killifish

A killifish is any of various oviparous cyprinodontiform fish . Altogether, there are some 1270 different species of killifish, the biggest family being Rivulidae, containing more than 320 species...

 and topminnows.

It can grow up to 12.9 centimetres in length and 21.4 grams in weight. The male is dark green with a yellow underside and a dark spot on the dorsal fin

Dorsal fin

A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...

 when spawning. The female is brown or olive in colour, paler below.

It was formerly common in fresh and brackish ponds and marshes throughout Bermuda. It has a declined as a result of destruction and modification of its habitat by humans and was listed as a protected species in the Bermuda Protected Species Act of 2003. It is currently known from just seven ponds: Mangrove Lake, Trott's Pond, West and East Walsingham Ponds, Warwick Pond, Evan's Pond and an introduced population in Blue Hole Pond. The populations in Lover's Lake and Bartram's Pond are now thought to be a separate species, Lover's Lake killifish (F. relictus). Some of the other populations of Bermuda killifish may also be separate species.

It is omnivorous

Omnivore

Omnivores are species that eat both plants and animals as their primary food source...

 and its diet includes green algae

Green algae

The green algae are the large group of algae from which the embryophytes emerged. As such, they form a paraphyletic group, although the group including both green algae and embryophytes is monophyletic...

, molluscs, crustacean

Crustacean

Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...

s and insect

Insect

Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...

s. Its predators include heron

Heron

The herons are long-legged freshwater and coastal birds in the family Ardeidae. There are 64 recognised species in this family. Some are called "egrets" or "bitterns" instead of "heron"....

s, grey snappers and American eel

American eel

The American eel, Anguilla rostrata, is a catadromous fish found on the eastern coast of North America. It has a snake-like body with a small sharp pointed head. It is brown on top and a tan-yellow color on the bottom. It has sharp pointed teeth but no pelvic fins...

s as well as the introduced

Introduced species

An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...

 eastern mosquitofish

Eastern mosquitofish

The eastern mosquitofish, Gambusia holbrooki, is a species of freshwater fish that is closely related to the western mosquitofish, Gambusia affinis. It is a member of the family Poeciliidae of order Cyprinodontiformes...

 and red-eared terrapin.