The Ruby River has surpisingly prolific hatches for a smaller volume fishery. The river below Ruby Reservoir benefits from the stability produced by the dam upstream and these stabilization of flows helps aquatic insects to thrive. Strong emergences of insects as well as abundant terrestrials keep trout well fed much of the season. The Ruby enjoys good late winter midge hatches that can entice trout to the surface in the later winter months. Blue winged olive hatches are prevelant later in the spring on cloudy days. Early summer kicks off a strong pale morning dun hatch. The broad agricultural valleys on the lower river can are home to large populations of hoppers in the late summer months.
Midges
Midges are a major source for food on the lower reaches of the Ruby River. Midges range in size from 16 to 26, with most midges on the Ruby River size 18 to 22. Midges can hatch year-round, but the late winter produces the most important hatches. Other times of the year the midge larva are important as subsurface food source. Dry fly action can often be found over midge hatches in late January, February and March. Any subsurface tandem nymph rig on the Ruby River should always include a pattern that imitates a midge, such as a Zebra Midge.
Blue Winged Olives (BWOs)
These dark-bodied mayflies hatch on the Ruby River during two seasonal windows—late March through mid-May and again in mid-September, lasting well into October. Overcast days may see the strongest emergence, but sunny days can also experience very strong hatches as well. The ideal BWO day on the Ruby River is overcast, with scattered showers, and air temps in the low 50s. Spring BWOs range from size 14 to 16 and fall BWOs range in size from 16 to 22. Most BWO hatches occur mid-morning or early afternoon and can last several hours.
Caddis
Caddis on the Ruby River hatch from late April through August, with strong hatches in early May, June, and July. Because the Ruby River is a tailwater—the stream flows are regulated by Ruby Dam near Alder—a strong emergence of caddis occurs around Mother’s Day. The Ruby River is home to a large amount of caddis species, so from mid-April through August, the potential for a strong caddis hatch exists most days. Because the Ruby River is home to a variety of caddis species, attempting to identify them all would be cumbersome. It is also not necessary for catching more fish. Caddis nymphs on the Ruby River are active year-round and run from size 10 to 22 and can provide subsurface action even if the river’s trout are not rising to hatching insects.
Pale Morning Duns
These summer-time mayflies hatch in abundance on the Ruby River. Pale Morning Dun (PMDs) begin to hatch in mid-June and last all through July. Primarily found in the river’s riffles and longer runs, PMDs emerge when water temperatures hit 58 degrees F. PMDs hatch on sunny or overcast days on the Ruby River and they can hatch in either condition. Nymphs are available to trout year-round, but during a hatch, the hatching insects require time to allow for their wings to dry before taking flight, therefore being easily available to a sipping trout. Most PMDs are size 14 and 16, with size 16 being the most common.
Yellow Sally stoneflies
The Ruby River isn’t known for producing large hatches of stoneflies—especially the larger species of salmonflies or Golden stoneflies—however, consistent hatches of Yellow Sally stoneflies do occur on the river in large quantities from Ruby Dam downstream to Silver Springs Bridge. Yellow Sally stonefly nymphs become active in early June, with adult insects hatching from early-June well into July. Yellow Sally nymphs range in size from 8 to 16, with size 10 and 12 being the most common. Because adult Yellow Sallies have very sporadic flying habits, trout rarely key on them making fishing dry flies difficult, but the nymphs are consumed on a daily basis.
Trico mayflies
As the heat of summer builds and hatches of PMDs slow to a trickle, trico mayflies provide a technical, sight-fishing option for dry fly anglers on the Ruby River. These small, black-bodied and white-winged insects usually hatch at sunrise in late July and throughout August. An emergence rarely lasts longer than a few hours. Adult tricos swarm in mating swirls above the water, after mating they fall to the water and die, creating “spent” mayflies, also called “spinners” by many anglers.
Terrestrials: Grasshoppers, ants, beetles, and crickets
When late July hits, many of the Ruby River’s more consistent hatches become sporadic and less predictable. Fortunately, because the Ruby River is bordered by hay and grass fields, an abundance of land-based insects find their way into the river. Grasshoppers, ants, beetles, and crickets dominate a trout’s diet by late July. Having been blown into the river these land-dwelling insects are a common occurrence on the Ruby River. Once on the water they become easy prey for hungry trout. Most grasshoppers are sizes 8 to 12 and most ants and beetles are size 14 to 18. Colorations vary but natural tones like gray and tan tend to fish better than bright colors.
October caddis
October caddis can hatch as early as late September and will typically peak in late October. Compared to other hatches, an emergence of October caddis is limited to a few flying insects in a given section of the river. But an opportunistic trout may feast on one of these large caddis species if it happens to float by at that same time a fish feels hungry. Most October caddis are size 8 to 10.
Streamers
Although not a hatch, it is important to understand streamers on the Ruby River. Because the lower Ruby River is predominately a brown trout fishery, anglers should always consider using a streamer pattern. The Ruby River boast plenty of ideal habitat for aggressive brown trout that include undercut banks, overhanging and submerged structure, and turbidity at a level that is conducive to large trout feeling comfortable ambushing prey. Streamer fishing on the Ruby River is possible any day of the year, with peak activity occurring late spring and late fall.