Bloater
Coregonus hoyi
Coregonus hoyi, also known as the bloater, is a species or form of freshwater whitefish in the family Salmonidae. It is a silvery-coloured herring-like fish, 25.
3
Countries
Photo: Wikimedia Commons (CC) via https://en.wikipedia.org/wiki/Coregonus_hoyi
Taxonomy & Classification
Kingdom
Animalia
Phylum
Chordata
Order
Salmoniformes
Family
Salmonidae
Genus
Coregonus
Bloater belongs to the family Salmonidae, order Salmoniformes, within the unknown class.
Species Profile
Coregonus hoyi, also known as the bloater, is a species or form of freshwater whitefish in the family Salmonidae. It is a silvery-coloured herring-like fish, 25.5 centimetres (10.0 in) long. It is found in most of the Great Lakes and in Lake Nipigon, and inhabits underwater slopes. This fish is not to be confused with the extinct deepwater cisco, a large fish that shared a common name with the bloater.
The Bloater faces significant threats from habitat degradation in the Great Lakes ecosystem, where invasive species and water quality changes have disrupted its deep-water environment. Climate change is altering thermal stratification patterns in these lakes, affecting the cold, oxygen-rich waters this species requires for survival and reproduction.
Key Facts
Habitat & Distribution
Deep, cold waters of the Great Lakes, typically found in profundal zones at depths of 40-200 meters where temperatures remain consistently cold year-round. Prefers well-oxygenated hypolimnetic waters with soft substrates where it feeds on zooplankton and small invertebrates.
Threats
Climate change altering lake thermal structure
Invasive species competition and predation
Water quality degradation and eutrophication
Habitat loss from coastal development
Overfishing and bycatch in commercial fisheries
Found in 3 Countries
Community Sightings
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Sources & Attribution
How to Cite
IUCN: IUCN (2025). The IUCN Red List of Threatened Species. Version 2025-1. Available at: https://www.iucnredlist.org. doi:10.2305/IUCN.UK.2025-1.RLTS
GBIF: GBIF.org (2025). GBIF Home Page. Available at: https://www.gbif.org
This page: SpeciesRadar (2025). Bloater (Coregonus hoyi). SpeciesRadar: Intelligence for Earth's Biodiversity. Available at: https://speciesradar.org/species/bloater