Flathead catfish

Quick facts

Adult size

90 cm, 8000 g typical harvest weight

Days to harvest

730 to 1095 days from fingerling

Lifespan (max)

up to 28 years

Diet

carnivore

Temperature class

warm-water

Difficulty

intermediate

Water parameters

Temperature range

8–32°C (optimum 27°C)

pH

6.5 to 8.5

Hardness

5 to 25 dGH

Minimum tank

1500 L per individual at harvest size

Feed and growth

Feed protein

40% target

Daily feed (warm water)

2.00% of body weight per day

Daily feed (cool water)

0.80% of body weight per day

Max stocking density

30 g per litre of system water

A 8000g adult eats about 160.0 g of feed per day at optimum temperature. For a roster of 10 fish at adult size, that's around 1600 g of feed daily.

Legality

Aquaculture and possession rules vary by jurisdiction and change over time. This table reflects regulations as of the verified date on each row. Verify with your local fisheries or wildlife authority before stocking.

Jurisdictions not listed here default to "check local regulations". A non-listing is not a green light; rules in your specific county or municipality may apply.

Habitat and origin

Native to the Mississippi, Missouri, and Ohio River basins and Gulf Coast drainages across the central and southeastern United States. The species (Pylodictis olivaris) is the second-largest catfish in North America after the blue catfish, reaching over 50 kg. Flathead catfish are solitary ambush predators that inhabit deep pools, undercut banks, and log jams in large rivers. Unlike channel catfish and blue catfish (which are omnivorous scavengers), flathead catfish are almost exclusively piscivorous: they eat live fish and crayfish, and have difficulty transitioning to dead or pelleted food. The flesh is white, firm, and widely considered the best-tasting of any North American catfish species. Flathead catfish are invasive in several eastern US river systems where they've been introduced for sport fishing.

Climate and outdoor ponds

Climate classification

temperate (handles seasonal swings)

Outdoor pond zones (USDA)

5 to 11 (winter low around -29°C or warmer)

Heating in a temperate climate

Not required (handles seasonal cool periods)

Cooling in a temperate climate

Not required

Zone bounds reflect year-round outdoor pond viability with no active heating. Anywhere outside the bounded zone, the species can still be kept in an indoor heated tank or a seasonally-managed system. Verify your specific microclimate, as a sheltered yard zone can run a half-zone warmer than the regional rating.

Care notes

A challenging aquaculture species not recommended for most aquaponics setups. The core problem is feeding: flathead catfish are live-food predators that strongly prefer to catch and eat live fish. Training them to accept pelleted feed is extremely difficult; most individuals refuse pellets even after extended conditioning. This means growing flathead catfish typically requires a supply of live feeder fish, which is expensive, labor-intensive, and defeats the efficiency advantages of pellet-based aquaponics. Growth on live feed is moderate: 500–1 g in 18-24 months. FCR data on pelleted diets is sparse because so few fish accept pellets. Temperature range: 10–32°C, optimal at 24–28°C. For operators determined to try, small fingerlings (under 5 cm) have the best chance of pellet training; larger fish are nearly hopeless. Stocking must be single-size cohorts in separate compartments because flathead catfish are aggressively cannibalistic. Low density (5-10 g/L) is necessary because they're solitary and territorial. Fingerlings are available from a few southern US hatcheries. The flesh quality is exceptional, but the culture difficulty makes this species impractical for aquaponics.

Further reading

• Aquaponics water chemistry: balancing pH for fish and plants
• Fish for aquaponics: tilapia vs everything else