Department of Environmental Conservation

D E C banner

Smaller Unusual Fish Species That Anglers May Encounter

Note: This article first appeared in the March/April 1992 issue of The Conservationist magazine. Recently updated. Authors- John Hasse & Eileen C. Stegemann. Ninth in a 14-part series describing the Freshwater Fishes of New York.

Because of the large number of unusual fish species found in New York State waters, this category of fish has been divided into two articles. In the November-December 1991 issue of The Conservationist, Part I discussed the larger unusual fish that anglers might encounter. Below we discuss a few of the smaller species of New York State's unusual fish.


picture of mosquitofish

Mosquitofish have a limited range in New York State - found only in the New York City and Long Island areas. A small fish, they rarely reach over two inches in length.

Mosquitofish live in slow-moving or stagnant water in small water bodies. They are dull grey or brown in color and are almost always found near the water's surface eating their favorite food: mosquito larvae. Their mouths are located on the top of their heads, a perfect adaptation for surface feeding.

Mosquitofish are the only freshwater fish in the state that give birth to their young rather than laying eggs. Male mosquitofish have a modified anal fin (shaped somewhat like a tube) that aids in reproduction. Three to four weeks after mating, the young are born looking like miniature adults. In contrast, the young of egg-laying fish look quite different from adults by having a large egg sac which they absorb.

Mosquitofish were first introduced into New York's waters as a biological control for mosquitoes. Although it was originally hoped they could be put into waters across the state, their need for warmer waters has prevented this from occurring.

Banded Killifish

picture of banded killifish

Found in various waters across the state, banded killifish live in weedy shallows of lakes and ponds and in slower-moving parts of streams. They are small fish, averaging two to three inches long.

Killifish have flattened heads with upturned mouths and large eyes. Although they look similar to female mosquitofish, killifish differ by having a series of 12 to 20 dark vertical bars on their sides.

While their upturned mouths would indicate they are surface feeders, killifish will feed any place in the water. They often feed in schools, eating insects, snails and flatworms. When frightened, killifish will sometimes dive into the soft bottom to escape.

Spawning occurs in weedy areas of quiet water. At this time, male killifish become quite aggressive, actively defending territories against other males. During spawning, females initially lay a single large egg that remains attached to their bodies by a thin thread. After some chasing by the males, females lay five to ten additional eggs which are then fertilized. The eggs then break free from the female and sink into the vegetation where they are left unguarded. Hatching takes place in two weeks.

Other than occasional use as baitfish, killifish have little contact with anglers.

Central Mudminnow

picture of central mudminnow

Small, robust-bodied fish, central mudminnows only reach two to four inches in length. They are generally dark brown with mottled sides and have a prominent black bar at the base of the tail.

Mudminnows live in a number of waters across the state, including the Great Lakes and the Champlain, Mohawk, and Upper Hudson River drainages. They are mostly found in heavily vegetated areas with a thick organic material layer. When disturbed, mudminnows dive into these soft muck bottoms.

Mudminnows are hardy fish that can survive in waters where other fish cannot, such as swamps and stagnant pools. Their ability to gulp air at the surface enables them to live in these waters with low oxygen levels and high temperatures.

Central mudminnows feed along the bottom. Similar to members of the pike family, they remain motionless in vegetation and then dart out to grab a food item. They primarily eat aquatic insects, mollusks, and other small aquatic organisms.

Spawning takes place in April in shallow, weedy water at the edge of ponds and streams. The sticky eggs are scattered over vegetation. No parental care is given.

Other than serving as bait for anglers, these secretive little fish are rarely utilized by man.

Brook Silverside

picture of brook silverside

Brook silversides are slender, nearly-transparent fish covered with fine scales. They have large eyes and long, almost beak-like jaws. Their name comes from the bright silver streak that runs down their sides. They are small fish, rarely reaching more than four inches in length.

Brook silversides are found at the water's surface in weedy areas of streams and lakes. Young silversides form large floating schools in open water during the day, but disperse at night. Though delicate looking, silversides are efficient predators for their size. They eat small aquatic animals and insects, frequently leaping out of the water when chasing flying insects.

Silversides spawn in and around aquatic vegetation during June and July. Males defend territories and mate with females after a short chase that usually involves leaping out of the water. The orange colored eggs contain numerous oil globules and a long adhesive filament that acts as an anchoring device. Short lived adults only spawn once before dying.

Brook silversides are found in the St. Lawrence River, the Finger Lakes area, and Lakes Erie and Ontario and their tributaries. They have little interaction with people.

American Brook Lamprey

picture of American brook lamprey

American brook lamprey are the only nonparasitic lamprey found in New York State. Their disc-like mouths contain poorly developed teeth, useless for attaching to a host.

Brook lamprey have long, wormlike bodies. Their dark skin is smooth and leathery and without scales. They average six to eight inches in length. Brook lamprey are only found in clear, cold brooks and small streams.

Unlike most other New York fish, the brook lamprey does not have a skeleton made of bone; rather it is made of cartilage. In addition, brook lamprey lack a spinal cord. Instead, these fish have a notochord which functions in the same manner as the spinal cord.

Spawning takes place in spring. The males (aided by females) construct small nests by picking up pebbles with their mouths and moving them to form the rims of shallow depressions. The sticky eggs are deposited in the nest and adhere to the sand and gravel. Adult brook lampreys die after spawning.

When they first hatch, young lamprey are called ammocoetes. Ammocoetes burrow into the sand and silt where they live for five years, feeding on microscopic plant and animal life and detritus (decaying matter). Shortly before spawning, ammocoetes metamorphose (change from one body form to another) into sexually mature adult fish. Adult brook lamprey cannot eat, since they have a nonfunctional intestine, and only live for four to six months.

Pirate Perch

picture of pirate perch

Pirate perch are only found in two areas of New York State: a few small streams west of Rochester and numerous Long Island streams. They live in shallow, weedy water areas with slow current and plenty of soft muck and organic material.

Stubby, heavy-bodied little fish, pirate perch have interesting features. Their eyes are small but their mouths are large and upturned. One of the bones near the gill cover, called the preopercle, has a rough, saw-toothed edge. Pirate perch differ from other fish species in that as they mature, the location of their body openings (anus and urogenital) moves from the rear portion of the body up to between the gill openings.

Pirate perch spawn in May. Both parents build a nest and guard the eggs and young. Adult pirate perch eat insects and an occasional small fish.

Brook Stickleback

picture of brook stickleback

Brook stickleback are very interesting fish. Their odd appearance and elaborate spawning behavior make them an intriguing species to watch. Many high school biology classes have used sticklebacks to demonstrate the concept of animal behavior.

Brook stickleback have prominent mouths, large eyes and four to six spines on their backs. Their smooth bodies do not have any scales, but tiny bony plates are found on their sides. They are found across the state in clear, cold water wherever dense vegetation is common.

Brook sticklebacks display some of the most interesting spawning behavior of all New York State's freshwater fishes. Male sticklebacks build elaborate, golf ball sized nests of dead grass, fine fibers, and algae cemented together with body secretions. The hollow nest has both an entrance and an exit hole. Using a series of nips, butts, and nudges, the males lure females inside the nest. Once the eggs are deposited, males then chase the females out of the nest. This process is repeated so that several females deposit eggs in the same nest. Male sticklebacks remain with the nest, fanning the eggs and then guarding the nest and young against all intruders.

Brook sticklebacks eat a variety of organisms, including aquatic insects and eggs and larvae of other fish. They have little contact with people.

Scientific Names

Many species of fish look alike, making it difficult to tell them apart. In addition, many types of fish have different common names in different parts of the country. To distinguish one organism from another, biologists give each a scientific name that is unique to that organism. The names are derived from the Latin language and consist of a genus and a species. The genus name is first and is capitalized. The species is second and is in lower case. Both the genus and species are either underlined or italicized when written. While several organisms in the same "family" share a common genus name (like family members sharing a last name), they have different species names. Occasionally, two members of a family are so similar that one is considered a subspecies of the other. In these cases, the organisms are given two species names. Here are the common and scientific names of New York State's unusual fish:

Scientific Names of Fish Species
Common Name Scientific Name
mosquitofish Gambusia affinis
banded killifish Fundulus diaphanus
central mudminnow Umbra limi
brook silverside Labidesthes sicculus
American brook lamprey Lampetra appendix
pirate perch Aphredoderus sayannus sayanus
brook stickleback Culaea inconstans

More about Smaller Unusual Fish Species That Anglers May Encounter:

  • Important Links
  • Contact for this Page
  • Bureau of Fisheries
    625 Broadway
    Albany, NY 12233-4753
    Send us an email
  • This Page Covers
  • Page applies to all NYS regions