Fundulus olivaceus

Blackspotted Topminnow
Conservation status
Least Concern  (IUCN 3.1)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Cyprinodontiformes
Family:	Fundulidae
Genus:	Fundulus
Species:	F. olivaceus
Binomial name
Fundulus olivaceus (D. H. Storer (fr), 1845)

Fundulus olivaceus is a species of fish in the family Fundulidae, the topminnows and North American killifishes. It is known by the common name blackspotted topminnow.^[1] It is native to the south-central United States, where it is known from the drainages of the Mississippi River from Illinois to the Gulf of Mexico and as far west as Galveston Bay.^[1]

This fish has an elongate body up to 9.7 centimeters long. It is brownish yellow to olive green on its upper side and has a wide, dark lateral band and distinct dark spots. The male has longer fins than the female and the fins of the male may take on a yellowish color during breeding. This species is very similar to the blackstripe topminnow (Fundulus notatus), which also has a dark lateral band. It can be distinguished from F. notatus by its darker, more numerous spots. The two may hybridize.^[2]

This species lives in clear streams with fast currents and sand or gravel substrates. It can often be found near the thick vegetation along the banks of the streams. It is omnivorous, consuming some plant matter along with a main diet of insects and other arthropods.^[2]

The fish spawns between March and September, its spawning season peaking around May. Males are aggressive toward other males and actively court females. The male and female come together to spawn in the gravel bottoms of the streams. The eggs are about 2 millimeters wide and are attached with filaments, forming a tuft. They hatch within two weeks. The life span of the fish is probably about 3 years.^[2]

References