Speckled Dace Rhinichthys osculus
Conservation Status: Not listed under the Endangered Species Act
> Speckled Dace is known to hybridize with other minnows such as Pike Minnow, Chiselmouth, and Redside Shiners.
> Because the populations of Speckled Dace have been separated so many times in the past, throughout Canada and the Pacific Northwest there is a large number of subspecies.
> Speckled Dace is the most common occurring minnow in Oregon.
Identification Tips
> Juvenile Speckled Dace usually have a dark stripe along both sides of the body from mouth to tail.
> They have a wide or thick caudal peduncle.
> Speckled Dace have rounded-edge fins.
> Speckled Dace have a slightly down-turned mouth.
Natural History
> Speckled Dace tend to school in large numbers in streams as well as in ponds and lakes.
> They breed in spring and prefer riffles, if available, for spawning. In lakes they select areas with gravelly bottoms.
> During the breeding season, individuals display spawning colors and tubercles. Before spawning, the males build nests for females to lay their eggs and become protective of the nest site. Once the female enters the nest, however, she is swarmed by multiple males. Females tend to leave and re-enter nests multiple times to lay several clutches of eggs. Eggs adhere to the bottom. Most of the eggs that do not end up under rocks are likely to be eaten by Dace. Eggs develop rapidly and within a week free-swimming juvenile Dace will hatch.
> Adult Speckled Dace become sexually mature when they are 2 to 3 years old.
Range
> Speckled Dace are widespread throughout the western United States. Populations are found as far north as British Columbia and as far south as Sonora, Mexico.
> In Oregon, Speckled Dace can be found in all large river systems, lakes, seasonal watercourses, and streams.
Size
> These fish range in size from 2 to 4 inches (5 to 10 cm).
Habitat
> This species is known to inhabit both slow and fast reaches of rivers but can also live in lakes and other still-water systems.
> In rivers, they tend to congregate in riffles or margins of pools.
Diet
> Speckled Dace are omnivorous bottom feeders that consume benthic aquatic plant material and macroinvertebrates.
> Adults occasionally feed on insects on the surface or drifting in mid-water.
> Young and juveniles eat primarily zooplankton.
Conservation and Management
> From 2011–2013 to 2021–2023, there was no apparent change in abundance or occupancy in the Willamette River.
Similar Species
> Longnose Dace, which have barbels on their snout.
> Leopard Dace, which have barbels on their snout.
References
For more information, see references.