Crayfish vs Crawfish: Where Do Crayfish Live?
Crayfish are freshwater crustaceans found all over the U.S.
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Crayfish vs crawfish, and what is the difference? They are the same freshwater crustaceans. Learn where crayfish live, how to catch crayfish, and crayfish tank setup and care.
by Mark Hall
It’s a hot mid-summer afternoon, and our little ones are ready to cool down with one of their favorite pastimes. They pull on their tall rubber boots, grab their buckets, and head for the shed. There, each one picks out a long-handled net and slings it onto her shoulder like it’s a hobo stick. Shaded by a stand of maples and teeming with aquatic life, our creek is calling. It’s a siren song that they simply can’t resist.
Crayfish vs Crawfish?
There are always fascinating creek dwellers for our amateur explorers to carefully capture and eagerly study. Their all-time favorite is the crayfish. Dependent upon where you live, you may instead know this freshwater crustacean as the crawfish, the crawdad, or even the mudbug.
The crayfish has an interesting appearance. It comes in several different colors, including brown, red, green, blue, and a pale yellow. Its head sports two sets of antennae, a sharp beak, and two tiny compound eyes, located at the tips of two independently moving stems. The head and thorax are connected by a hard shell made of calcium and phosphate, called a carapace. This entire body segment, known as a cephalothorax, looks much like that of a lobster. However, with an average adult length of three inches, the crayfish is dwarfed in size by its nearly two-foot relative.
The crayfish has 10 legs protruding from the cephalothorax. The front pair is large and ends in mighty claws that enable the creature to smash and tear its food. Immediately behind are the other four pairs that maneuver the crayfish forward or sideways. These legs also gather and hold food while eating.
The abdomen, with its flipper tail, is also like that of the lobster. This body segment has a total of six sections, each with its own pair of tiny appendages. Shaped like paddles, these appendages, also called swimmerets, aid in moving water for respiration and swimming. At the end is a horizontally oriented tail fan.
If threatened, the crayfish flips its tail under its body and contracts its powerful abdominal muscles to quickly launch itself backward. However, if a predator has already seized its leg, the crayfish has another trick. It has specialized joint muscles that allow it to disconnect the leg, leaving it behind in the mouth of the predator while the rest of the crayfish swims safely away. Amazingly, the leg then regenerates during successive molts.
How to Catch Crayfish
Upon arrival, the young adventurers drop their gear and begin to scan the whole area. Crayfish burrow to avoid predators, so our kids turn over rocks in the shallow creek bottom and along its banks. Many live almost entirely underground, reappearing only to eat and to mate. Digging tunnels up to several feet deep, crayfish can stay damp far below ground in underground streams, even during severely dry periods. Deep burrowing in winter keeps them below the frost line, making hibernation unnecessary.
If the kids are fortunate enough to find one, they’ll bring it to the house and place it in a small aquarium. This excitement is closely followed by a trip to the pet store to buy a little jar of crayfish food. Inside each of these pellets is a blend of protein and other nutrients. Before we leave the store, we often can’t resist the purchase of a sunken treasure ship, some underwater foliage, or some other fun piece of aquarium décor.
Crayfish Tank Setup & Care
The kids are currently caring for a crayfish they’ve named May. As with any pet, some work is certainly necessary in caring for her. Every week, her aquarium, plus all its decorations, must be cleaned, and her creek water must be changed. However, it’s little sacrifice for the immense enjoyment of her presence.
As a crustacean, May has a hard exoskeleton, but she continually needs room to grow. This space can only result from a frequent shedding, or molting, of her shell. Every two months or so, a split develops between the abdomen and the carapace, allowing May to emerge with a new, soft shell that will harden a few days later. The old one is wholly left behind, complete with antennae and eye coverings. Her old exoskeleton isn’t removed from the aquarium, since eating it provides calcium and other nutrients needed for future molts. To avoid distracting her from this culinary mission, she isn’t fed for the next few days. As she ages, molting will become less frequent, slowing to only two or three times per year.
Crayfish have a high ecological value. First of all, they provide a crucial link in the food chain. They eat a wide variety of aquatic organisms, such as plants, snails, insect larvae, small fish, and dead things on creek bottoms. At the same time, crayfish are themselves eaten by more than 200 wild animals, such as larger fish, water birds, and raccoons. Second, by chewing organic matter, they make it more usable as food for smaller animals. Finally, since they’re susceptible to water pollution, crayfish are indicators of water quality.
Crayfish Varieties
Tremendous variety exists among crayfish. Incredibly, more than 500 species are found across the globe, and nearly 70 percent of those species live in the United States. The vast majority are in freshwater lakes, ponds, and streams, while others are in swamps and marshes. A few species are even found in brackish or salty ocean water.
The crayfish is considered a delicacy in Europe and in many other parts of the world. Backyard crawfish boils are popular throughout the southern United States, often cooked with Cajun spices. The state of Louisiana produces more than 100 million pounds of crayfish per year, or around 90 percent of the U.S. crayfish market. Not surprisingly, it’s the official crustacean of Louisiana, and the industry adds more than $300 million to the annual state economy.
My family has learned a great deal about crayfish. May, our most recent teacher, often studies us from under her favorite little ceramic bridge, crawling out in anticipation when we lift the lid to drop in her pellets. She’s so smart, you’d never know she once lived under a rock!
Editor’s note: Laws for catching crayfish vary by state, so check your local rules and regulations before heading out.
Resources:
- “Crayfish.” Encyclopedia Britannica, 12 Nov. 2024. Accessed 13 Nov. 2024.
- “Detailed Guide to Regeneration in Crustaceans.” Aquarium Breeder. Accessed 13 Nov. 2024.
- Helfrich, Louis A., and DiStefano, Robert J. “Sustaining America’s Aquatic Biodiversity—Crayfish Biodiversity and Conservation.” Virginia Cooperative Extension, 24 March 2020. Accessed 13 Nov. 2024.
- “History.” Louisiana Crawfish Promotion and Research Board. Accessed 13 Nov. 2024.
Mark M. Hall lives with his wife, their three daughters, and numerous pets on a four-acre slice of paradise in rural Ohio. Mark is a veteran small-scale chicken farmer and an avid observer of nature. As a freelance writer, he endeavors to share his life experiences in a manner that is both informative and entertaining.
Originally published in the March/April 2025 issue of Countryside and Small Stock Journal and regularly vetted for accuracy.
