Stop 13: Stream Species

Speckled brown fish swimming near rocks
Speckled dace.

Photo by Bruce Taubert, courtesy Arizona Game and Fish Department

Speckled Dace

Depending on where you are in Arizona, the speckled dace (Rhinichthys osculus) looks different. In the southern part of the Gila River system, they are small, with lots of speckles or blotches, and chubby-bodied. North of the Mogollon Rim, they are larger, may or may not have bands, and their shape is more streamlined. They can grow up to three inches (7.6 cm) long on a diet of algae and other plants, small crustaceans, insect larvae, and small snails. Speckled dace are bottom dwellers found in smaller, shallow rivers. They don’t do well in water with high temperature or low oxygen content.

Conservation status: Least Concern

Threats: Non-native predatory fish

Desert Sucker

The desert sucker (Catostomus clarki) uses a cartilage ridge below its lower lip to scrape food from the bottom of stream channels. It feeds on diatoms, algae, and any small animals that happen to be within the algae. Juveniles eat small aquatic insects, such as midge and blackfly larvae. Desert suckers typically grow to 13 inches (33 cm) in length. They are abundant in the Bill Williams, Gila, Salt, and Verde river systems. They require streamflow, as opposed to lake conditions, and prefer waters that include quiet pools with gravelly or rocky bottoms.

Conservation status: Least Concern

Threats: Loss of habitat and food sources through alteration of flow regimes and construction of reservoirs; non-native fish stocking.

This is the end of the tour. You may retrace your steps to the front of the building or exit through the gate near the cistern at the northeast corner of the main building.

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Last updated: April 22, 2022