Resilient California Fishes: Lahontan Redside Shiners

By Peter B. Moyle and Thomas L. Taylor

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The fresh waters of California support a diverse, highly endemic fish fauna. Many of the native fishes are on extinction trajectories. In this blog series, however, we discuss native fishes that are not considered to be in trouble. Instead, they are native species that have sufficient resiliency to keep populations large and sustainable, even in highly altered habitats. Information on these species should help us to understand why they have such resiliency in the face of large-scale changes to California waterways. This blog is the fifth in a series that started with an account of the Sacramento Sucker (Moyle and Taylor 2025). Visit the “Resilient California Fishes:” tag to see all the posts in this series as they are posted.

An underwater view of a school of Lahontan Redside Shiners. There is a lot of open blue water. — Figure 1. Typical school of Lahontan Redside hanging around a boat dock in Fallen Leaf Lake. The school will venture out from the cover of the dock, picking invertebrates and pine pollen off the surface, then turn and quickly dive back toward the cover of the dock when threatened by any movement. These are one and two-year-old fish, now growing into adulthood. Photo by Tom Taylor; 31 August 2014.

If you have been to Lake Tahoe and seen a loose school of small fish under a pier or other cover, you were probably looking at Lahontan Redsides (aka Lahontan Redside Shiners).

Pleistocene Distribution

The Lahontan Redside minnow is an abundant relic of the Pleistocene era, when much of northern Nevada was under the waters of the giant Lake Lahontan. When this lake‘s level was high, its northwestern shores were in California, where water flowed in from the predecessors of the Carson, Walker, Truckee, and Susan Rivers. Eagle Lake also drained into Lake Lahontan. The largest remnant of Lake Lahontan is Pyramid Lake in Nevada, still fed by the Truckee and Humboldt (Nevada) rivers. The present-day native distribution of the Lahontan Redside coincides with the historical extent of Lake Lahontan and its tributaries. This range is also that of several other native fish species. The shiner is notable for being abundant in Eagle Lake (Lassen County), where the pH is unusually high, usually around 9, and summer temperatures can be on the warm side.

A map of Lake Lahontan. — *Figure 2. The extent of Pleistocene Lake Lahontan in eastern California and Northwestern Nevada*. *Map Credit: Matthew Trump*.

Early Scientific History

The scientific name for the Lahontan Redside is Richardsonius egregius, given to it by Charles Girard in 1858, when he described the species based on one specimen. The first part of the name (genus) is in honor of Sir John Richardson, a physician who described the only other species in the genus. Why he gave the species the name egregius, which translates as “surprising”, is not known, but perhaps Girard had an adult specimen that had traces of the bright colors of spawning fish. Alternatively, he could have been surprised to find the species at all, given that the only other Richardsonius is a common fish in the distant Columbia River watershed.

In any case, the Lahontan Redside is abundant in the rivers of the eastern Sierra Nevada in California. It is also found in Lake Tahoe and Eagle Lake, as well as in smaller lakes and some reservoirs, where they feed opportunistically on aquatic invertebrates. The pioneering California fish biologist, John Otterbein Snyder, wrote about the Lahontan Redside in his monograph on fishes of the Lahontan Basin: “It delights in the slow riffles and the quiet shallow pools where large numbers can be seen lazily swimming about over the submerged bars, occasionally turning their silvery sides to the bright sun. In the lakes it congregates in large schools, swimming about submerged logs, tops of fallen trees, wharfs, and other sheltered places (1918, 54).”

A dark underwater image of a huge school of small fish. The water color is black and teal. — Figure 3. A massive school of Lahontan Redside hangs around a submerged pine tree off the south point of Baldwin Cove in Fallen Leaf Lake in the Lake Tahoe Basin. The photo was taken while snorkeling. I have not seen this level of abundance in the 40 years since then. The population may have been augmented by preceding wet winters. Photo by Tom Taylor; 6 June 1986.

A spawning group of Lahontan Redside Shiners; they are tan but have a vibrant red stripe on the side of their bodies. — Figure 4. A spawning aggregation of Lahontan Redsides cover the bottom of Taylor Creek (no relation). The swarm of fish is actively swimming and interacting with each other as they swim to the bottom in small groups to expel eggs and milt near the bed of the creek. I found it fascinating that this aggregation was essentially invisible from above the creek and the bank. It wasn’t until I got into the water that the colorful sides were evident. Photo by Tom Taylor; 24 May 1987.

The Big Show is Spawning

The colors of spawning fish are bright, with a wide scarlet stripe along the belly, bordered by a black stripe and topped with a golden-yellow stripe that extends all the way to the tail. Their backs are olivaceous, and the belly can be silvery to white. Bright red is actually a protective color because red is the first color of the visible spectrum to be filtered out by water, so the fish are hard to see, especially at night or if hanging out in deep shade.

Spawning fish also develop tiny nuptial tubercles on the sides and fins, which are bigger in males than females (see figures 5 and 6) and may function in sexual selection, like antlers in deer, or they may help to protect the scales from excessive abrasion as fish rub against one another while spawning. Spawners move into streams in large numbers to spawn together in shallow riffles and runs. These aggregations can be spectacular to watch, although the behavior has been characterized as confusing, because the swirling groups of fish make it hard to see what individual fish are doing. The red band on each side of the fish usually fades after spawning to a mostly overall gray fish, but can still be visible on fish that are 3-6 inches long and 3-6 years old (Moyle 2002).

A close up of: A spawning group of Lahontan Redside Shiners; they are tan but have a vibrant red stripe on the side of their bodies. — Figure 5. A group of Lahontan Redside during spawning activities in Glen Alpine Creek, the main inflowing stream to Fallen Leaf Lake. Spawning occurs around a water temperature of 15^oC in the spring and early summer. In the Fallen Leaf Lake system, this means that spawning can occur in the outlet stream (Taylor Creek) that is fed by relatively warmer surface spill from the lake, mid to late May, and in the colder, snowmelt-influenced inflow of Glen Alpine Creek in July. Note the spawning tubercles on many of these fish. Photo by Tom Taylor; 17 July 2016.

A close up of a single fish: A spawning colored Lahontan Redside Shiner. It's easy to see tiny bumps over the body. — Figure 6. Close-up of a three-inch male Lahontan Redside in Glen Alpine Creek displaying full spawning regalia. The spawning tubercles are one on each scale and along the fin rays. During spawning, there is lots of physical contact between males, probably in competition for females. The tubercles protect males from damage by other males, and males with a dense array of tubercles may be favored by females. Photo by Tom Taylor; 4 July 1990.

Ecosystem Function

Because of its abundance and wide distribution, Lahontan Redsides are undoubtedly important as prey for piscivorous fish, such as Lahontan Cutthroat Trout, and birds such as mergansers, herons, and pelicans. There is also evidence they were consumed by the Paiute people, who could easily catch them in traps when large numbers moved up small streams to spawn (Fowler and Bath 1981). Reservoirs can also support populations of Lahontan Redside, provided there is an inflowing stream available for spawning, such as in Sagehen Creek, which flows into Stampede Reservoir.

There are also a number of records of Lahontan Redsides colonizing streams and lakes outside their native range, mostly in the Sacramento -San Joaquin watersheds, due to water projects and bait-using anglers (Moyle 2002). However, they do not appear to have spread widely from these introduction waters. Regardless, the Lahontan Redside has demonstrated its resilience through its flexibility in habitat use (from cold water streams to large lakes), opportunistic diet, and a physiology that allows it to persist at a wide range of temperatures and alkalinities. Therefore, we would not be surprised if Lahontan Redsides started appearing in sampling programs in the western Sierra Nevada and habitats in the Sacramento River and tributaries. These little fish can be found through the shallower water of Lake Tahoe and in the rivers and lakes in the Truckee, Walker, Carson, and Susan river systems, and in Nevada. In short, the Lahontan Redside is a very resilient fish species. We expect it to grace the waters of California and Nevada for the indefinite future.

A close up of a rocky underwater floor; there is no fish. — Figure 7. The rocky, angular substrate of Glen Alpine Creek is sprinkled with developing ova of Lahonton Redside. The newly fertilized eggs are clear, denser than water, and quickly settle into the crevices where they stick to the bottom, even in areas with turbulence and current. The whitish component of these eggs is the developing larvae. Photo by Tom Taylor; 4 July 1990.

An underwater view of yearling Lahontan Redside Shienrs. — Figure 8. These are yearling Lahontan Redside inhabiting the shoreline of Fallen Leaf Lake. The size of these fish indicates they were spawned the previous year. They have spent one summer, fall, and winter growing to this size and will grow into adults by next summer. Photo by Tom Taylor; 24 May 1986.

About the Authors

Peter Moyle is Distinguished Professor Emeritus at the University of California, Davis, and is Associate Director of the Center for Watershed Sciences.

Tom Taylor has had a long career as an agency and consulting biologist, often working with native fishes. He has also taken underwater photos of many of the fishes, which will illustrate the blogs.

Further Reading

Beauchamp, D.A., Byron, E.R. and Wurtsbaugh, W.A., 1994. Summer habitat use by littoral‐zone fishes in Lake Tahoe and the effects of shoreline structures. North American Journal of Fisheries Management, 14(2):385-394.

Fowler, C.S. and J.E. Bath 1981. Pyramid Lake Northern Paiute fishing: the ethnographic record. Journal of California and Great Basin Anthropology 3 (2) 176-186.

Moyle, P.B. 2002. Inland Fishes of California, Revised and Expanded. University of California Press.

Snyder, J.O.1918. The fishes of the Lahontan system of Nevada and northeastern California. Bulletin of U.S. Bureau of Fisheries 35: 31-86.