Cisco Fish (Lake Herring): ID, Range and Eating

• Mouth: the lower jaw reaches the tip of the snout or slightly beyond it (terminal mouth). This is the single best mark (Minnesota DNR; North Dakota Game and Fish).
• Colour: silver with pink and purple iridescence, a deep blue-green back and a white belly (USFWS).
• Fins: light and nearly clear, except dark tips on the tail and dorsal fin (USFWS).
• Body: slender, elongate and elliptical (USFWS), with an adipose fin like a trout.
• Size: most adults are 10 to 18 in; Minnesota's state record cisco is 5 lb 11.8 oz, against 12 lb 4.5 oz for lake whitefish (Minnesota DNR).

No, but they are close relatives in the same genus, Coregonus, and are often caught together. Check the mouth: on a lake whitefish the snout overhangs the mouth (subterminal), while on a cisco the lower jaw reaches the snout tip or just past it (North Dakota Game and Fish). Cisco also stay smaller, which is why North Dakota notes that anglers sometimes mistake an average whitefish for a record cisco.

The name "lake herring" is misleading too: the cisco is not a true herring but a member of the trout and salmon family. A third silvery fish, the mooneye, is told apart by its large eyes (Minnesota DNR). See our guide to common fish look-alikes.

Cisco live in the open, midwater zone of cold lakes across northern North America, and in large rivers in the north and west (Wikipedia). In the Great Lakes they are native to all five lakes and to Lake Nipigon, Ontario, usually at depths of 270 to 450 ft, moving into 3 to 10 ft of water to spawn (USFWS). They spawn in fall and winter.

They have become scarce in many places. Wikipedia reports the species is now common only in Lake Superior, with the Lake Huron population recently increasing and Lakes Erie and Ontario severely depleted. Farther south, cisco need cold, oxygen-rich deep water that many lakes lose in summer: Indiana listed cisco as state endangered on 17 December 2020 after the number of lakes holding them fell sharply (Indiana DNR). North Dakota has them in the Missouri River system, including Lake Audubon (North Dakota Game and Fish).

Cisco, northern cisco, lake herring, chub and tullibee (Wikipedia); Eat Wisconsin Fish adds bluefin. The Anishinaabe (Ojibwe) name is odoonibiins.

Cisco is a traditional food fish, and Lake Superior herring is sold fresh, smoked and frozen. Eat Wisconsin Fish describes it as clean-tasting, light and delicate, more buttery than lake whitefish, with omega-3 levels per ounce similar to sockeye salmon. Its roe is sold as bluefin caviar, and Wikipedia notes international demand for cisco roe.

Whether a particular fish is fine to eat depends on the water. For Lake Superior herring, Eat Wisconsin Fish gives mercury as the main concern and lists up to 8 meals a month for the general population, but 1 meal a week for women under 50 and children under 15. Check your own state's advisory for the lake you fished; the EPA says contamination cannot be seen or smelled.

Lay the fish flat on its side and photograph the whole body, then take a close, sharp side view of the head with the mouth closed, so the position of the lower jaw against the snout is clear. That one frame separates cisco from lake whitefish. Include the adipose fin and the dark-tipped tail. FishLens names the likely species from the photo; use the marks above to confirm it.

Cisco limits differ by state and by lake, and in Indiana the species is state endangered. Check the current regulations for the water you are fishing before keeping any cisco, and if you are unsure of the species, release it.

Research and drafting for this page were assisted by AI and checked line by line against the sources listed below. Every number names the organisation it comes from, and where sources disagree we say so instead of picking one silently. Prices carry the date we checked them (25 September 2026); they change, so confirm before you rely on them. If you find an error, tell us and we will correct it.