Bloater
Bloater are a deep-water cisco native to the Canadian Great Lakes and Lake Nipigon in Ontario.
They're not a recreational target — they live too deep for most anglers to reach — but they're a cornerstone of the Great Lakes food web, serving as critical forage for lake trout, burbot, and historically, Atlantic salmon.
Their story in Canada is largely one of collapse and slow restoration.
Also known as cisco, deepwater cisco, lake bloater
- Cylindrical and laterally compressed, deepest through the midsection and tapering sharply toward the head and tail — a classic torpedo shape for a deep-water fish.
- Silver overall with a white belly and a noticeable iridescence — flashes of pink, purple, and green — along the sides.
- Fins run pale yellow to nearly transparent; no bold markings to distinguish them from other ciscoes at a glance.
- Typical length runs 10–14 inches; when brought to the surface, the gas bladder expands visibly, which is exactly how they got their name.
What to know
Habitat Distribution
- Native to Lakes Superior, Huron, Michigan, and Ontario, and to Lake Nipigon in Ontario; absent from Lake Erie, which is too shallow for their needs.
- Now considered extirpated from Lake Ontario and Lake Nipigon; active reintroduction efforts have been stocking hatchery-raised fish into Lake Ontario since 2012.
- A deep-water species through and through — they occupy depths from roughly 90 to 600 feet, spending daylight hours near the bottom and moving into open water at night to feed.
Key Locations
- Lake Superior and Lake Huron — the two Canadian Great Lakes where self-sustaining bloater populations still exist in deep offshore waters.
- Lake Ontario — the focus of ongoing reintroduction efforts; over a million hatchery fish stocked since 2012, though a wild-reproducing population has not yet been confirmed.
- Lake Nipigon, Ontario — historically native, now considered extirpated.
Specific Spots
- Deep offshore basins are their core habitat during the day — structure in the traditional sense doesn't apply here; depth itself is the holding feature.
- At night, bloater move up into the water column to feed on zooplankton and small invertebrates, making them briefly accessible in shallower open water.
- During spawning, adults concentrate in deep water — historical accounts from Lake Michigan point to depths greater than 55 meters with no particular substrate preference.
Bloater FAQ
Answers from onWater's species guide.
How do you catch Bloater?
Bloater are not a recreational target in Canada. They live at depths that put them well beyond the reach of sport fishing, and their zooplankton-based diet makes them nearly impossible to catch on conventional tackle.
What do Bloater eat?
Bloater feed almost entirely on zooplankton, freshwater shrimp, and amphipods (small crustaceans), filtering them from the water column, not a predatory fish in any conventional sense.
Where do Bloater live?
Native to Lakes Superior, Huron, Michigan, and Ontario, and to Lake Nipigon in Ontario; absent from Lake Erie, which is too shallow for their needs. Now considered extirpated from Lake Ontario and Lake Nipigon; active reintroduction efforts have been stocking hatchery-raised fish into Lake Ontario since 2012.
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