Fish Most active at dawn and dusk

Cisco

Coregonus artedi

iNaturalist Wikipedia

Discover the silver ghost of the Great Lakes. The Cisco is a master of the deep, known for its shimmering schools and vital role in the cold-water ecosystem.

0 Sightings

0 Habitats

Quick Identification

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Size

Typically 25–40 cm (10–16 inches) long and weighing 0.5–1.4 kg (1–3 lbs)

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Colors

Iridescent silver sides with a dark blue, emerald green, or violet-tinted back and a white belly

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Key Features

Distinctive adipose fin between the dorsal and tail fins
Terminal mouth where the lower jaw often projects slightly forward
Deeply forked tail fin
Slender, streamlined body built for speed

When You’ll See Them

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Activity pattern Most active at dawn and dusk

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Peak hours 5-8 AM, 6-10 PM

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Season October-December

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Diet Ciscoes are planktivores, primarily filtering zooplankton like daphnia and copepods from the water, though they also consume aquatic insect larvae and small crustaceans.

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Habitat Deep, cold freshwater lakes and large rivers with high dissolved oxygen levels.

public Geographic range

Where Does the Cisco Live?

Native to the northern regions of North America, the Cisco is a hallmark species of the glacial lakes found throughout Canada and the northern United States. Their primary range encompasses the Great Lakes basin and extends northward through the boreal forests of Ontario and Quebec into the Arctic drainages of the Northwest Territories. They are also found across the upper Midwestern states, including Minnesota, Wisconsin, and Michigan, where they inhabit deep, inland 'two-story' lakes that remain cold year-round.

Basemap © OpenStreetMap contributors

2 Countries

8.5M km² Range

Least Concern Conservation

CA Canada US United States

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iNaturalist / Verified observation data

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Behavior

Ciscoes are highly social, schooling fish that act as a vital link in the food web of North America’s cold-water lakes. They are primarily pelagic, meaning they spend the majority of their time in the open water column rather than near the bottom or the shore. Known for their daily vertical migrations, they typically move toward the lake surface at night to feed on plankton and retreat to the safety of dark, oxygen-rich depths as the sun rises.

These fish are exceptionally sensitive to environmental changes, particularly rising water temperatures and declining oxygen levels, often serving as indicators of overall lake health. While they are usually wary and keep their distance from human activity, they congregate in massive, shimmering schools during the late autumn. During this spawning period, their behavior shifts as they move into shallower waters, providing a rare opportunity for lakeside observers and underwater cameras to witness their synchronized movements.

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Camera Tips

To capture the silver flash of a Cisco, you will need to move your EverydayEarth setup underwater. For those with lakefront property or access to a dock, the most effective method is mounting an action camera or a specialized underwater trail camera to a dock piling or a weighted tripod lowered to the lakebed. Aim the camera at a depth of 3 to 8 feet over a patch of clean gravel or cobble. These areas are magnetic to Cisco during their late-autumn spawning run (November and December), which is the only time these deep-water specialists venture into shallow 'backyard' depths.

Lighting is the biggest challenge for underwater photography. While Cisco are active during the day, their most impressive schooling behavior often occurs at twilight. Use a camera with high-quality infrared (IR) LEDs to capture crisp black-and-white footage without spooking the fish. If your water clarity is low, try placing a small, submersible green fishing light about five feet away from the lens. This light attracts zooplankton, which in turn draws the Cisco directly into your camera's field of view for a feeding frenzy.

For the best results, set your camera to record high-definition video rather than still photos. Cisco are incredibly fast swimmers, and a 20-second video clip better captures the mesmerizing, fluid motion of a school than a single still image. Be mindful of the cold; as water temperatures drop toward freezing during the peak Cisco season, battery life can diminish rapidly. Using fresh lithium batteries or an external underwater power pack will ensure you don't miss the peak of the autumn spawning run.

Similar Species

Species that look similar or are commonly confused with Cisco.

Lake Whitefish

The Whitefish has an overhanging upper jaw and a blunt snout, whereas the Cisco has a pointed snout and a forward-facing mouth.

Rainbow Smelt

Smelt are much smaller, thinner, and possess prominent teeth on their tongue, which Cisco lack entirely.

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Frequently Asked Questions

Cisco are crepuscular, meaning they are most active during the low-light hours of dawn and dusk. This is when they perform vertical migrations to the surface to feed on plankton.

Since Cisco are fish, you can only attract them if your 'backyard' includes a deep, cold lake. Submersible lights near a dock can attract the zooplankton they eat, occasionally drawing schools closer to your underwater camera.

Cisco are primarily planktivores, meaning they eat microscopic animals called zooplankton. They also occasionally feed on small shrimp-like crustaceans and aquatic insect larvae.

They are only common in suburban areas that border large, deep glacial lakes in the Northern US and Canada, such as the communities surrounding the Great Lakes or Lake Mendota.

Look at the mouth: the Cisco has a 'terminal' mouth that points straight forward, while the Lake Whitefish has a 'subterminal' mouth that points downward for bottom feeding.

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