What Do Crayfish Eat? Nutrition Facts & FAQ
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The crayfish goes by many names. You’ll also hear them called crawdads, crawfish, or yabbies. Whatever their moniker, they have specific food needs, whether in their native habitats or in a tank. The former varies widely and affects what’s available. Crayfish are omnivores and along with plants, they will eat insects, aquatic crustaceans, snails, and even worms.
Crayfish are part of the phylum Arthropoda, which includes a vast array of invertebrate species, like insects. The subphylum to which crayfish belong is Crustacean. That group contains many familiar species, such as shrimp and lobsters.
Crayfish Around the World
Over 640 crayfish species exist worldwide. They consist of two superfamilies: Astacoidea of the Northern Hemisphere and Parastacoidea of the Southern Hemisphere.
- Astacidae family
- Cambaridae family
- Cambaroididae family
- Western North America and Europe
- Canada, North America, and Central America
- Eastern Asia
The Parastacoidea consists of one family, the Parastacidae, of which there are over 170 species in New Zealand, Australia, South America, and other countries in the South Ocean.
The Cambaridae is the largest of the three families, containing over 330 of the extant or living representatives. Astacidae has 13 species, while Cambaroididae only has six. These numbers suggest that we’d see the greatest diversity in diet with the Cambaridae family. If you consider its range, species of this group occupy a broad range of ecosystems and habitats. That points to a diverse diet.
The Diet of Wild Crayfish
Crayfish are omnivores, which means they’ll eat both plants and meat. The latter term covers a wide range of protein sources, including insects, aquatic crustaceans, snails, and even worms. This is a function of where these crustaceans live. These animals are ravenous eaters to the point that they can become destructive invasive species.
Crayfish aren’t picky eaters by any means. This generalist strategy gives these species an evolutionary advantage that helps them survive in a dog-eat-dog world. Crayfish can roll with the punches and still meet their nutritional needs. A species that specializes in one food is vulnerable without a backup plan.
Astacidae
The Astacidae family lives in a diverse range of habitats throughout the European continent, parts of Canada, and the Pacific Coast. Most species are freshwater, although some also live in brackish water. These areas affect their diet and prey base. Some species have a different diet based on their age. For example, young Austropotamobius torrentium eat animal proteins, whereas adults prefer plants.
Cambaridae
The Cambaridae family is the largest of the three crayfish groups by far, with over 400 species. North America is home to over 330 alone. With so many members, the diet of these crustaceans covers many foodstuffs. They’ll eat insects, small fish, and mollusks, such as snails and clams. Since they are omnivores, crayfish will also feed on vegetation and decaying organic matter.
Cambaroididae
The Cambaroididae family is the smallest group, with only six living species. They often occupy narrow ranges and are prevalent in only a few countries. Therefore, their diet shows the same specialization, with similar diversity in food items. It’s worth mentioning that this group contains the only species found in Asia.
Parastacidae
The Parastacidae family lives in a wide range of habitats, with some species even found in Antarctica. Interestingly, there are none on the African continent nor are there any living representatives in the Northern Hemisphere. The diversity of their native habitats means the diets of these crustaceans will reflect an equally broad spectrum of foods.
The Diet of Captive Crayfish
These crustaceans are opportunistic feeders that will eat just about anything they can find, including fish. That fact will play a role in what tank mates to add to your crayfish’s aquarium.
Getting crayfish to eat what you offer them depends on their environment. Like their wild counterparts, they are nocturnal animals. You should provide cover for them to hide during the day. Research has shown that stress can affect these crustaceans too, which can in turn, affect their appetite.
Suitable foods that you can offer your crayfish include things that you’d give other bottom feeders, such as pleco wafers, sinking pellets, and greens. They will readily eat vegetables, like peas and spinach. They will also eat live aquarium plants. However, crayfish can destroy whatever plants you put in your tank.
Crayfish molt and shed their skin in early summer. But don’t be tempted to remove it. These crustaceans will make short work of it to gain back the calcium that it contains.
Final Thoughts
Crayfish are interesting creatures on several scores. Their history goes back about 265 million years ago to the early Triassic Period. They’ve adapted to a wide range of habitats and still bring those wild traits to the aquarium. If one thing is certain, you won’t have any problems feeding your crayfish.
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Featured Image Credit: SritanaN, Shutterstock
