The Peace/Williston Fish and Wildlife Compensation Program (PWFWCP)

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Redside Shiner
Richardsonius balteatus

What do they look like?

A deep bodied, laterally compressed minnow with the origin of the dorsal fin well behind the pelvic fins, a deeply forked caudal fin, and an unusually high number of anal rays (10-22). Young-of-the-year redside shiners often occur in mixed schools with young peamouth and pikeminnows. They are separable from young peamouth by the relative position of the dorsal and pelvic fins (the dorsal fin in redside shiners originates well behind the origin of the pelvic fins) and from young pikeminnows by the absence of a dark spot at the base of the caudal fin.

Spawning males are often brilliantly coloured with a gold patch under the eye and a bright yellow-gold stripe above the mid-lateral line and crimson flanks. The colours in females are more subdued with the lower flanks a pale pink rather than crimson.

Where do they live?

In the interior of British Columbia, redside shiners are common in low altitude streams, rivers, ponds, lakes, and reservoirs. During the day, in the summer, adults cruise the littoral zones of lakes, usually in water less than 4 m deep. They forage in small, alert groups, constantly moving, aggressively pushing into weed beds, checking out items on the bottom, and darting to the surface. At night they move offshore. In rivers, redside shiners usually occur in relatively deep (1-2 m), slow (<0.20 m/s) water over fine substrates.

In summer, in lakes, juvenile redside shiners occur in loose schools around lake margins. Usually they are in shallower water and closer to shore than adults. Similarly, in the summer, young-of-the year redside shiners occur in shallow water (usually less than 1 m) along lake margins. Typically they are associated with aquatic vegetation and occur in mixed schools with underyearling peamouth and northern pikeminnows. In streams and rivers, young redside shiners prefer quiet water (less than 0.1 m/s), fine-grained substrates, and water less than 0.5 m depth. They are abundant in shallow backwaters and weedy bays.

What is their life like?

Apparently, spawning in redside shiners is triggered by the spring rise in water temperature. The threshold temperature is about 10 °C (April to June). In British Columbia, spawning occurs primarily in flowing water over clean gravel substrate. Some populations spawn in lakes but most lacustrine populations, spawn in inlet or outlet streams. At these sites, redside shiners rarely ascend or descend the stream for more than a few hundred metres and spawning usually occurs on the first or second riffle above or below the lake. Some populations spawn at night and others during the day.

Typically, ripe fish mill slowly about in a pool or low velocity area below a riffle until a female swims rapidly upstream into the riffle. When this happens, an entourage of males (often four or five) immediately join her and crowd against the female. The female may release several batches of eggs over a period of one or two minutes and then return to the holding area. Over the course of the spawning period, each female spawns many times and with many different males. The eggs are adhesive. As in most fish, fecundity is a function of body size and egg number ranges from about 700-4,000 eggs. The eggs take about five days to hatch at 18°C and the newly hatched fry are about 6 mm long.

Young-of-the-year begin feeding at about 8 mm, and grow rapidly in their first summer. Depending on latitude and food availability, they are 25-40 mm long by the end of the growing season. Males reach sexual maturity in their third summer and most females mature a year later. The maximum life span recorded in B.C. is 6 years (5+).

What do they eat?

Young-of-the-year redside shiners consume a variety of prey including organisms taken from both the bottom and the water surface (e.g., diatoms, cladocerans, copepods, ostracods, and chironomid larvae and pupae). As they grow, shiners take larger prey. Adults forage in the littoral zone where they take prey from the bottom, from mid-water, and from the surface. Nymphs and pupae of aquatic insects, and adult terrestrial insects, dominate their diet but they also take cladocerans, copepods, molluscs and, in season, the eggs and fry of fish (including their own species).

What is their distribution? The redside shiner is native to western North America. Its original distribution was from the Nass system in the north to the Great Basin (Utah and Nevada) in the south. In B.C., Richardsonius is primarily an Interior species, although redside shiners reach the coast in large rivers like the Fraser and Skeena. They have a low tolerance for seawater and do not reach any of the coastal islands. They do occur from the Columbia to the Nass River in the north. Redside shiners reached the Skeena from the Fraser system and the Nass from the Skeena system. They also entered the upper Peace system from the Fraser.

View Peace Williston distribution map.