Freshwater · Best in spring during spawning runs; April to June in Colorado basin rivers
Flannelmouth Sucker
Catostomus latipinnis
One of the Colorado basin's great native big-river fish, and part of the native-fish conservation story of the Grand Canyon reach. The name fits: its lower lip is hugely enlarged and fleshy, like a pad of flannel built for scraping food off river rock. A bottom specialist of big desert rivers, it is taken on worms and small baits fished deep in the channel.
Seasons · Peak
Identifying features
- Enormously thick, fleshy lower lip — the 'flannelmouth' that gives it its name
- Large, broad dorsal fin (the Latin latipinnis means 'broad-finned')
- Streamlined sucker body, olive-brown above and pale below
- Downturned sucker mouth set well under a blunt snout
- Small scales and a deeply forked tail for life in strong current
Habits
- Scrapes algae and invertebrates from rocks with its fleshy lips
- Holds in deep pools and channel runs of big canyon rivers
- Makes spring spawning runs into smaller tributaries
- One of the native 'big river' fishes monitored and conserved in the Grand Canyon
- Feeds mainly by day in clear desert-river water
Distribution
Where to find them
- Colorado River through the Grand Canyon and Cataract Canyon
- Green and Yampa rivers in Utah, Wyoming and Colorado
- Spring runs in tributaries such as the Paria and Little Colorado mouths
Where they live
How to catch them
Bottom fishing Colorado system channels River
Rig: Medium rod, slip-sinker rig and size 4-6 hooks fished on the bottom of deep channel runs in the Colorado, Green and Yampa rivers
Bait/lure: Nightcrawlers, small dough balls
Key tip: Fish deep and slow in the main channel; bites are soft plucks as the fish mouths the bait with its thick lips.
Canyon river spring-run fishing River
Rig: Light to medium bottom rigs with worm bait cast into tributary mouths and pool tails during the spring spawning run
Bait/lure: Worm pieces, crayfish
Key tip: Spring fish concentrate at tributary mouths — fish the edges of the current and handle these natives carefully for release.
Best baits & lures
Baseline setup
- Rod: Medium 7 ft spinning rod
- Line: 8-12 lb mono
- Terminal: Size 4-6 hooks, slip sinkers, split shot
Recommended gear for this species
Rod · Best value
9' 5-weight fly rod outfit
≈ US$180-260
Covers chironomid lakes and small rivers with one setup.
Flies · Budget
Chironomid assortment (30 patterns)
≈ US$25-40
Chironomids are 60% of a lake rainbow's diet in spring.
Picks come from our rule library — never paid placements. Prices are guides; affiliate links may earn us a commission.
Typical size
Common 15-24 in and 2-5 lb (38-61 cm, 0.9-2.3 kg); large fish to about 30 in (76 cm)
On the table
Poor to fair — bony sucker flesh; as a valued native of the Colorado basin it is best released, and rules vary by water.
Similar species
White SuckerWhite sucker is a smaller, widespread northern fish with much thinner lips; flannelmouth sucker is a big-river Colorado basin native with a hugely thickened, fleshy lower lip and a broader dorsal fin
Roundtail ChubRoundtail chub is a minnow with a normal small terminal mouth and no sucker lips; flannelmouth sucker has a downturned scraping mouth with thick fleshy lips and a much larger buildRegulations vary by area and can change in-season — always check the official rules for your area before you fish. Regulations guide →
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