Iowa DNR
River & Stream Biological Monitoring
Fish and Benthic Macroinvertebrate Surveys
Physical Habitat Assessments

Brook Silverside Labidesthes sicculus

Atherinopsidae (Silversides)
Trophic Class
Is Exotic to Iowa?
Is Lithophilous Spawner?
Is Hybrid?
State Listing Status
Not Listed
Assessment Program Statistics

This species was found at 15 bioassessment sites, 0 rapid fish bioassessment sites, 2 fisheries assessment sites, and 0 fisheries presence-only assessment sites. In total, it was collected at 17 distinct sites, or 1.2% of the 1442 total sites monitored by the bioassessment program. It is the 95th most commonly collected species.

The Brook Silverside was collected in 19 bioassessment sampling sessions and 2 fisheries assessment sessions. It was present in 0 rapid bioassessment sessions and 0 presence-only sessions.

The biological assessment program has collected a total of 139 individual Brook Silverside specimens, ranking it the #90 most collected fish.

Species Characteristics

A very slender, elongate and translucent fish. Its head is flattened with a beak-like snout and a lower jaw that slightly projects toward the front. Upper and lower jaws have tiny, needle-like teeth. The long, sickle-shaped anal fin has one spine and 20 to 26 rays. Two dorsal fins are on the posterior half of the back. The first dorsal has 4 spines, and the second has one spine and 5 rays. Scales are small and cycloid with 75 to 84 scales along the lateral line. General body color is pale green. The dorsal scales are outlined with black specks, its sides are silvery with a bright silver horizontal stripe, and the belly is silvery-white. The fins are plain, except for a spinous dorsal fin and pigmentation near the tip. Adults usually average 2- to 4-inches long.

Species Distribution Maps

HUC12 watersheds where this species has been found