Longnose Killifish: Facts & Habitat

About Longnose Killifish

The longnose killifish (Fundulus similis) is a marine tropical benthopelagic fish of the genus Fundulus and the family Fundulidae. It is endemic to the western Atlantic Ocean, ranging from along the coast of the Gulf of Mexico from the Florida Keys to Tampico in Mexico. It can grow up to 12 centimeters in length. The body is rounded, elongate, and olive to silver colored with dark vertical stripes. It can be distinguished from other killifish by its long snout and a dark spot on last vertical bar. This species requires a new binomial, as Fundulus similis is preoccupied by a junior synonym of Fundulus majalis, the name having been given to a Gulf of Mexico population of that species.

NativeSalt6 states

Additional field notes

Longnose killifish is a slender fish of shallow coastal margins. The pointed snout, rounded tail, and narrow body bars provide a useful combination of field clues.

Sources: Fundulus similis species account

Field identification notes

The head is flattened above and the snout projects noticeably. Its small mouth opens near the front, and the fins have soft rays rather than spines. Both sexes can show narrow dark bars across an olive body and tail. Males may carry a dark mark near the upper corner of the gill cover.

Sources: Fundulus similis species account

Habitat and range notes

Bays, estuaries, and coastal marshes in brackish or marine water are the settings described by the Smithsonian. The regional account extends from northeastern Florida into the western Gulf of Mexico. It lists very shallow water, so a small shoreline fish should not automatically be assumed to be a freshwater minnow.

Sources: Fundulus similis species account

Feeding and life-history notes

The food categories include small crustaceans, mollusks, plankton, and microalgae. The name has a complicated taxonomic history involving Fundulus majalis; the catalog’s scientific name is retained here so that records and older references remain traceable.

Sources: Fundulus similis species account

Guide sources

Research reviewed 2026-10-17.

Fundulus similis species account — Smithsonian Tropical Research Institute

Article text: Wikipedia contributors, Fundulus similis (source revision). Licensed under CC BY-SA 4.0. Retrieved 2026-10-11.

Range

Where it lives

96.7%of mapped records

Share of 51,182 GBIF observation records with a state location, across 6 states.

Share of records by state

Habitat

Water and movement

Water: WoRMS records this species in the sea.

Classification

Taxonomy

Kingdom: Animalia
Phylum: Chordata
Superclass: Actinopterygii
Class: Teleostei
Order: Cyprinodontiformes
Family: Fundulidae
Genus: Fundulus
Species: Fundulus similis
ITIS TSN: 165657
WoRMS AphiaID: 276034
GBIF key: 5203634

Common questions about Longnose Killifish

What is the scientific name of Longnose Killifish?

The scientific name is Fundulus similis, in the family Fundulidae. Classification follows ITIS.

Does Longnose Killifish live in fresh water or salt water?

WoRMS records this species in the sea.

Where has Longnose Killifish been recorded in the United States?

GBIF has observations in 6 states, with the most records in Texas, Florida, Louisiana. The map shows observation records, which do not establish the complete natural range.

Closest relatives