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Lateral view of a Male Baetis (Baetidae) (Blue-Winged Olive) Mayfly Dun from Mystery Creek #43 in New York

Blue-winged Olives
Baetis

Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.

I like this one. Glacial river, taiga, tundra, and the perpetual ice cover of a massive high ridge dozens of miles away in the Wrangell Mountains.

From the Copper River in Alaska

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Sweltsa (Sallfly) Stonefly Nymph Sweltsa (Sallfly) Stonefly Nymph

Dorsal view of a Sweltsa (Chloroperlidae) (Sallfly) Stonefly Nymph from the Yakima River in Washington

This species was fairly abundant in a February sample of the upper Yakima.

10 Recently Added Photos

27" brown trout, my largest ever. It was the sub-dominant fish in its pool. After this, I hooked the bigger one, but I couldn't land it.

Troutnut is a project started in 2003 by salmonid ecologist Jason "Troutnut" Neuswanger to help anglers and fly tyers unabashedly embrace the entomological side of the sport. Learn more about Troutnut or support the project for an enhanced experience here.

Freshwater Invertebrate Underwater Pictures, Page 2

Freshwater Invertebrate Underwater Pictures, Page 2

Underwater photos of freshwater invertebrates in their natural habitat.

Mongaup Creek in New York

The white blotches on this rock are Leucotrichia caddisfly cases, and the wispy tubes are cases made by a type of midge.

Several fast-swimming Siphlonurus nymphs blend in very well with the silt in this slow backwater along a trout stream.

These are glossosomatids, Jason. They are probably Glossosoma nigrior, though it is possible that we are looking at mixed species. The ones to the right with their aggregate of similar sized grains are classic Glossosoma, while the ones to the left with the large anchor pebbles could possibly be Agapetus. Regardless, they're all commonly referred to as saddle case makers.

From Spring Creek in Wisconsin

The large caddisfly case (really less than 1/2 inch) is a Brachycentridae larva. The other cases are actually the protective sheaths of black fly (Simuliidae) pupae. The two antler-like pieces sticking out of each one are not legs, but antennal sheaths.

From Spring Creek in Wisconsin

Mongaup Creek in New York

There's a very well-camouflaged Baetisca laurentina mayfly nymph resting on the twig in the bottom left corner of this picture. Can you spot him?

Three big Ephemerella subvaria mayfly nymphs share a rock with some cased caddis larvae.

There's a large Ephemerella subvaria nymph in the top left.

A wide variety of caddis larvae and other insects have clustered together on the backside of this rock in fast water.

From Cayuta Creek in New York

This isn't really an underwater picture, but a picture taken into my aquarium of midge larvae which lived in the silt I used for substrate. Each larva has a little tower of detritus built up along the bottom, while the bare larva waves around from the top.

I lifted a rock in pursuit of a stonefly nymph that had scurried beneath it, and instead I found this Ephemera simulans burrowing mayfly nymph waiting to be photographed.

This tiny sculpin is the size of a mid-sized mayfly nymph.

From Fishing Creek in Pennsylvania

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