Flathead Catfish Habits
Fertilized eggs hatch in 6 to 9 days, depending on temperature, with larvae being from 11 to 14.8 mm in total length. A large, spherical yolk sac is present, and extends from the rear edge of the eye to the pelvic fin buds. The gills, mouth, and digestive system are all functional at this point, although the yolk sac is the primary source of nutrition until it is completely absorbed (at a total length of approximately 17.6 mm). Newly hatched individuals have rudiments of the future spines and rayed elements of the dorsal, pectoral, and caudal fins. All fins will generally attain full development by the time the yolk sac is absorbed. Like other ictalurid species, flathead catfish grow continuously, gradually attaining adult body proportions and coloration patterns. Adults can range from 58 mm to more than 1000 mm in length, depending on age, and there have been reports of individuals of over 1500 mm. They do not normally exceed 1000 mm until they reach 10 years of age.
- Development - Life Cycle: indeterminate growth
Flathead catfish mating systems have not been observed in the wild, but mating in captivity has been observed and documented. The male moved over and around the female, rubbing her with his belly and, apparently, his barbels. He then stopped swimming, with his tail surrounding the female's head, while making strong, quivering movements. This behavior was repeated periodically until the female was ready to spawn, 2 weeks later. At that time, the female deposited eggs in a depression that had been made in the aquarium gravel, which were then fertilized by the male. Total spawning time was approximately 4 hours, after which the female was removed and the male began ferociously defending the eggs, even from the female that had layed them.
Flathead Catfish Species Information
Learn more about this catfish species.
Mating System: monogamous
Age at sexual maturity appears to be regionally dependent, and can range from 3 to 5 years in males and 3 to 7 years in females. Spawning occurs in early to late summer, when the water temperature is 23.8 to 29°C, with eggs hatching 6 to 9 days post-fertilization. Nests are constructed under cover, including logs, stumps, brush piles, and rock outcroppings. The number of eggs produced by a female is positively correlated with her body size, and a single nest can contain up to 100,000 eggs. The eggs are adhesive, and are expelled in masses of 30 to 50 individual eggs.
- Breeding interval: Flathead catfish breed once yearly
- Breeding season: Spawning occurs in June and July
- Range number of offspring: 100,000 (high)
- Range time to hatching: 6 to 9 days
- Range age at sexual or reproductive maturity (female): 3 to 7 years
- Average age at sexual or reproductive maturity (female): 4 years
- Range age at sexual or reproductive maturity (male): 3 to 5 years
Males guard the eggs until they hatch, after which he will continue to protect the newborn fish for several days.
Flathead catfish occupy deeper parts of rivers and lakes. They are ambush predators, waiting in and under cover for their prey to cross their path. This species is primarily nocturnal, but is sometimes active during the day as well. Flathead catfish are mainly piscivorous, and are infamous for eating other game fish in the non-native areas where they have been introduced. They become mostly inactive when water temperatures drop below 10°C.
- Key Behaviors: natatoria,l nocturnal, motile, hibernation, solitary
- Range territory size: 0 to 3601 m^2
- Average territory size: 1135 m^2
Pre-fertilization provisioning protecting female pre-hatching/birth provisioning female protecting male pre-independence protecting male
Communication & Perception
The captive spawning activity discussed above indicates that tactile, and possibly chemical cues are used in communication between flathead catfish. This species is able to sense its environment using its eyes, mechanosensory lateral line, and the taste buds covering its body, which are concentrated on the barbels. Flathead catfish (like all otophysan fishes) have an improved sense of hearing due to the presence of their Weberian apparatus, which connects the swim bladder (which serves as a resonance chamber) to the inner ear.
- Communication Channel: stactile, chemical
- Perception Channels: visual, tactile, acoustic vibrations, chemical
Flathead catfish are carnivores that prey on many different types of animals, depending on size. They are known to eat crayfish, gizzard shad (Dorosoma cepedianum), insects and larvae, channel catfish (Ictalurus punctatus), drum (Aplodinotus grunniens), other flatheads (Pylodictis olivaris), green sunfish (Lepomis cyanellus) and carp. Insect larvae are the major prey type until an individual reaches approximately 100 mm in total length, at which point the diet expands to include crayfish and small fishes. Individuals above 250 mm in length feed almost exclusively on other fishes.
- Primary Diet: carnivore, piscivore, insectivore, eats non-insect arthropods
- Animal Foods: fish insects, aquatic crustaceans
Flathead catfish have no known predators other than members of their own species and humans who fish for them. Although, when they are larvae and younger, smaller fish, they are likely to be prey to other fish, wading birds, such as herons, and other medium-sized predators that forage in rivers and streams.
- Known Predators: Humans (Homo sapiens), Flathead Catfish (Pylodictis olivaris)
Flathead catfish serve as one of the top predators of other fishes in the areas they inhabit, and thus represent a potentially harmful invasive organism outside of their native range. This species has been observed to host over 25 different parasitic species, including several types of platyhelminth worms, nematodes, spiny-headed worms, leeches, copepods, water lice, and freshwater mussel larvae.
Sport fishing for flathead catfish using either rod and reel, limb lines, or bare hands (noodling) can be an exciting pastime. Anglers target this species in a variety of waterways, including small rivers (barely large enough for a canoe), large rivers (such as the Missouri, Mississippi, Ohio, Tennessee and Colorado Rivers), and reservoirs. A common element of flathead catfish location is submerged wood cover such as logs and rootwads which often collect at bends in rivers. A good flathead spot usually also includes relatively deep water compared to the rest of a particular section of river, a moderate amount of current, and access to plentiful baitfish such as river herring, shad, carp, drum, panfish, or suckers. Anglers targeting large flathead catfish usually use stout tackle such as medium-heavy or heavy action rods from 6–10 ft (1.8–3.0 m) in length with large line-capacity reels and line ranging from 20–80 pounds-force (89–356 N) test breaking strength. Generally large live baits are preferred such as river herring, shad, sunfish (such as bluegill), suckers, carp, goldfish, drum, and bullheads ranging from 5–12 in (13–30 cm) in length.