Kathy Johnson writes a column called “I Speak for the Fish” every month for Great Lakes Now. It comes out on the third Monday of every month. Publishing the author’s views and assertions does not represent endorsement by Great Lakes Now or Detroit Public Television. Check out her previous columns.
Searing pain raced up my nose and flooded my eyes with tears. Right after that, the silicone edge of my mask broke off from my upper lip, letting water pour in and up my nose.
A flooded mask was mildly annoying but nothing to panic over. However the intense pain radiating across my face definitely had the potential to induce panic. Lord, it hurt.
The diaphragm on my regulator vibrated loudly as I drew in a deep quivering breath. Unfortunately for me, my best option was to breathe deep and wait it out.
I was just hoping that the crayfish that was stuck on the tip of my nose wouldn’t stay there for too long. If it did, I was gonna need to shop for a nose ring after this dive.
Why was I so stupid? Why didn’t I see how bad this idea was before I went ahead with it? Harass a crayfish and then hold it close to your face. Sure, what could possibly go wrong?.
Crawdad, crawfish, or mudbug — a crayfish by any other name is still basically a miniature lobster. And a popular menu item in the Southern United States. I have only been to one crawfish boil in my life, so I would have to be really hungry and desperate to go to another one.
However, while a lobster tail is substantial enough to be considered a main course, a single crayfish tail is about the same as consuming one grape. Which is why crawdads are often served by the pail.
When websites and articles talk about the decline in crayfish populations, they usually blame habitat loss and invasive species. They don’t talk about all the backyard buckets that are full to the brim. I find the volume of animals killed per serving completely unappetizing and unnecessarily wasteful.
They love a good fish-egg breakfast followed by mayflies for lunch. In the afternoon, they might eat scuds as a snack before going back to their den, where the fish corpse chunk they put away yesterday would be ready for dinner.
While out of their den, crayfish are ever vigilant, as predators abound. Smallmouth bass particularly enjoy crayfish for breakfast, lunch, dinner and snack time.
Have you ever walked across a mowed lawn in a new neighborhood and seen a very small hole surrounded by little dirt mounds?
I always found them intriguing and even more so when I learned the holes were made by crayfish. It seemed highly improbable given the nearest body of water was usually miles away. Except there was enough water nearby, beneath my feet.
Primary burrowing crayfish spend most of their lives under fields, ditches, prairies and wet meadows. They live and dig tunnels well below ground that are at least as deep as the water table.
These burrowers can live up to 20 years. The Michigan Department of Natural Resources says that primary burrowing crayfish are good for animals to eat and help the soil breathe.
Secondary burrowers will go underground to escape drought, cold temperatures and predation. The underground holes they dig aren’t as complicated, though, and they might or might not have chimneys or piles of mud around them. Most secondary burrowers live only a short distance from permanent bodies of water such as streams and ponds.
Tertiary burrowers rarely, if ever, leave water and will only do so during extreme circumstances. They do their burrowing underwater. They typically excavate small caves under rocks and logs.
As both predators and prey, crayfish are important keystone species in the Great Lakes.
Crayfish also have the unique behavior of carrying their eggs and larvae under their tails. Makes sense. How better to keep them safe than being tucked under their mother’s tail?.
The eggs hatch as identical, transparent versions of the adults. But so tiny they could stand on the head of a pin. The minuscule larvae continue to hide under their mom’s tail for a couple more of weeks.
In the past, every professional underwater shooter had s of inflated puffer fish in their portfolios. Puffers live around coral reefs and they are covered with sharp spikes. In times of danger, puffers can blow up into a round, spiked ball that is very hard to swallow. It looks cool so some divers began grabbing, squeezing and otherwise harassing puffers just to make them inflate.
Today, credible editors would never publish those s. Even if the behavior occurred naturally and was not forced, showcasing a puffed puffer fish just promotes harassment.
One of the hot topics in underwater ethics centers around diver and marine life interactions. The generally held rule is don’t. Don’t touch anything. Don’t damage anything. Don’t injure anything. Don’t harass anything. Don’t feed anything.
Most divers dive in the ocean. And most recreational diving is done on or near coral reefs, where a careless touch of a hand or knee can hurt or damage a delicate marine animal. So, a hands-off approach really is best for all.
If a diver puts out their hand without thinking in fresh water, they are more likely to get hurt by a fishing lure that gets caught or by a razor-sharp zebra mussel shell. So, whether in saltwater or freshwater, we’re always cautious of where we put our hands and knees.
Harassment takes many forms. Forcing an animal to inflate or squirt ink or otherwise exhibit defend behaviors is textbook harassment. As is diving around whales, petting manatees or touching sea turtles.
To lessen the damage to local ecosystems, many places have started limiting the number of divers who can visit each day.
I really think it’s wrong to scare another animal, even if it’s just a crawdad. Sadly, the proof of my failing was still driving the point home on the end of my nose.
People often ask me to pose underwater so that the subject of the photoshoot is between me and the camera lens.
Having a diver in-frame is one of the easiest ways to show scale. A school of emerald shiners on a clear summer day makes a pretty picture. But adding a silhouetted diver in the distance helps people get a better idea of how big the school is.
Another way to show size was to hold small animals up to my face, which is something I used to do (note the past tense).
Initially, I had picked up the crayfish and held it at arm’s length towards the camera. If you know how to hold a crayfish, they are quite harmless. But with each picture, the camera got closer, and I brought the crayfish closer and closer to my face.
The crayfish did it out of desperation because there was a 1 in 100 chance that it would hit full. Too bad for me, the odds were in its favor that day. Even as my eyes watered and my face throbbed, I held no malice towards the crayfish.
It was a pain-filled lesson in not mistreating others. A significant life lesson driven home by a 4-inch crayfish.
I was lucky to know that, like many poisonous snakes, trying to pull a crayfish off usually makes it bite even harder.
Any hope of assistance from my buddy had already vaporized behind a wall of bubbles. As soon as the crayfish grabbed my nose, Greg began laughing so hard he drained half his tank.
Eventually, the crayfish would let go. Until then, all I could do was eat my just deserts.
With their big claws and armored bodies, crayfish can look quite intimidating to small fish This leads many aquarists to wonder – do crayfish eat fish? The answer is yes, crayfish are opportunistic omnivores that will eat fish if given the chance However, with proper tank setup and planning, crayfish and fish can co-exist in an aquarium.
Crayfish as Predators
In the wild, crayfish are ambush predators that live at the bottom of rivers, lakes and streams. They use their senses to detect prey movement and quickly snatch up any small fish, insect, worm or mollusk that comes near their hiding spot. Their large front claws allow them to easily capture prey and bring it to their mouth to consume.
While not fast swimmers, crayfish can move rapidly for short bursts to grab food. Once caught, the prey has little chance of escape from the crayfish’s strong grip. In addition to live prey, crayfish will scavenge any dead or decaying animals that sink to the bottom. Their powerful jaws allow them to tear apart flesh with ease.
When housed in an aquarium, crayfish retain these predatory instincts. Small, slow-moving fish make easy targets for hungry crayfish. Fast-moving schooling fish are safer tankmates, but lone fish resting on the bottom are at risk.
Crayfish may also attack fish while they are sleeping, catching them off guard. Even larger fish can become targets if they venture too close to a hiding crayfish ready to ambush.
Providing Proper Housing
While crayfish do prey on fish, they can successfully coexist together in a tank with careful planning. The key is providing an environment that reduces chances for aggression and allows fish to avoid confrontation. Some important factors include:
-
Tank Size – A larger tank gives fish more room to swim and reduces competition between species. A 40 gallon or bigger aquarium is recommended for housing crayfish with fish.
-
Hiding Spaces -driftwood, rocks and cave decor allow crayfish to feel secure while also providing visual barriers between species.
-
Planted Areas – Dense vegetation gives fish places to retreat and breaks up line of sight for crayfish. Floating plants are ideal since crayfish can’t climb up plants.
-
Tankmates – Active schooling fish like tetras, barbs and danios are less likely to become prey than slow, solitary fish. Avoid small species that will fit in a crayfish’s mouth.
-
Well-Fed Crayfish – Providing a variety of foods like algae wafers, veggies and sinking pellets helps curb predatory behavior in crayfish.
Crayfish Eating Molting Fish
One surprising way crayfish may consume tankmate fish is by eating freshly molted ones. All fish periodically shed their exterior scales as part of the molting process. This allows them to grow as their body size increases.
During this vulnerable molting phase, a fish’s protective slime coat is removed. Without scales and a slime barrier, the fish’s exposed skin secretes a protein that crayfish find irresistible. Even large, normally predator-proof fish may be attacked and consumed if encountered while molting.
To reduce chances of crayfish eating vulnerable molting fish, provide plenty of hiding spots in the tank. Increase the amount of plants and decor to allow fish to recover safely from a molt. Monitoring water quality is also important, as poor conditions can increase molting frequency.
Scavenging Fish Remains
In addition to preying on live fish, crayfish are efficient scavengers that will feed on deceased fish in the aquarium. Their strong claws and jaws allow crayfish to tear apart carcasses and consume scraps.
Crayfish scavenging on dead fish plays an important role in the closed ecosystem of a tank. They act as nature’s clean-up crew to remove decaying organic matter before it fouls the water.
However, aquarists should be cautious about allowing crayfish to eat fish killed by disease or parasites. Consuming infected tissue can transfer contagions to the crayfish and continue the spread. Remove and dispose of any diseased fish corpses promptly.
Providing Alternate Crayfish Foods
The key to keeping crayfish from viewing tankmates as food is providing a diverse diet. Well-fed crayfish are less likely to hunt fish for food. Offer a variety of foods including:
- Protein-rich frozen foods like bloodworms, brine shrimp, krill and mysis shrimp
- Sinking carnivore pellets or crayfish food
- Algae wafers or pellets to graze on
- Fresh veggies like zucchini, cucumber, peas and leafy greens
- Calcium-rich foods like spinach and kale for molting crayfish
Feeding crayfish at night when they are most active allows them to eat without competition from diurnal fish. Use sinking foods that make it through the water column to the bottom. While crayfish will scavenge leftovers, avoid leaving excess food to prevent water fouling.
Crayfish and Fry
One of the biggest risks of keeping crayfish with fish are vulnerable fry. Baby fish and shrimp fry provide bite-sized snacks for hungry crayfish. Even if the parents are too large to be considered prey, the babies make easy pickings.
Here are some tips to reduce losses if you want to raise fish fry with crayfish:
-
Remove brooding fish or shrimp mothers to a separate rearing tank to hatch fry.
-
Use a breeder box or mesh divider to keep crayfish apart from fry.
-
Provide dense thickets of plants for fry to hide in. Java moss makes a great refuge.
-
Feed crayfish well before introducing fry to reduce predation urges.
-
Add hiding caves just for fry that have small openings to exclude crayfish.
-
Introduce fast-moving fry like danios that can dart away from crayfish.
Preventing Crayfish Aggression
Territorial aggression is another reason crayfish may attack tankmates. Establishing dominance and claiming territory is common crayfish behavior. While fish are less likely to be viewed as rivals, confrontations can still occur.
Ways to curb aggressive behavior include:
-
Providing multiple shelters so crayfish don’t fight over one hiding place.
-
Rearranging decor weekly to eliminate established territories.
-
Keeping only one crayfish unless breeding. Don’t mix species.
-
Adding tank obstructions like large rocks that break up sightlines.
-
Feeding at opposite ends of the tank to prevent food competition.
Monitoring for Trouble
When first introducing any new tankmate, it’s important to monitor for signs of trouble. Look for torn fins, nipped tails or missing scales on fish. Also watch for fish suddenly hiding more or seeming stressed.
Pay attention to crayfish behaviors for clues, too. Are they spending more time away from shelters hunting? Do they posture aggressively with raised claws when fish swim by? These are red flags something may be wrong.
Reacting quickly at the first sign of trouble can prevent losses. Be prepared to separate bullies or move vulnerable fish to a different tank.
Avoiding Problematic Mixes
While many fish can coexist with crayfish, there are some notorious high-risk matches to avoid:
-
African cichlids are aggressive and likely to fight back if confronted.
-
Bettas may attack crayfish or get claws pinched in retaliation.
-
Gouramis and other anabantoids risk being eaten when they surface to breathe.
-
Slow moving fancy goldfish are essentially helpless against crayfish.
-
Shrimp and snails provide appetizer-sized meals for crayfish.
-
Small species like tetras and guppies easily end up as prey.
Peaceful Bottom Dwellers
On the other hand, there are some excellent tankmate choices compatible with crayfish:
-
Fast schooling fish like zebra danios, white cloud minnows and giant danios
-
Armored bottom fish like corydoras catfish and plecos that won’t get eaten
-
Medium-sized barbs, rainbowfish and larger rasboras unlikely to become meals
-
Bottom-dwelling synodontis catfish that can defend themselves
-
Larger clown loaches, yoyo loaches and other robust loaches
Crayfish are impressive predators equipped to catch live fish with their strong claws and armored bodies. However, by providing adequate space, hiding spots, tankmates and food, fish casualties can be avoided in a crayfish aquarium. With time and observation, you can find the right balance to allow both species to thrive together.
Do you have experience keeping fish successfully with crayfish? Share your tips and advice in the comments below!
Will Crayfish Eat my Other Fish?
How do crayfish eat?
In captivity, as pets, replicating the crayfish’s natural diet is pivotal for their health and wellbeing. Connect Fish Friends advocates for a diet that mirrors their natural consumption as closely as possible. This may include feeds like shrimp pellets, fish flakes, and vegetables such as peas and carrots to provide a balanced diet.
Do crayfish eat shrimp?
The crayfish will also snack on live aquarium plants if you keep any in the tank. If you’re feeding baby crayfish, you’ll need to crush their food small enough to fit into their mouths. Baby shrimp food is excellent for them, as it provides a good source of protein. Timing is also important.
Do crayfish eat temperature controlled food?
Every aspect of a crayfish’s diet, from commercially available foods to occasional household food items, must be considered in light of temperature. Feeding your pet crayfish in temperature-controlled water ensures that the balance of their diet is maintained.
Can crayfish eat frogs?
Keep in mind that crayfish is an opportunistic omnivore. They will eat absolutely anything they can catch (fish, snails, shrimp, frogs, and even other crayfish). Therefore, NO. It will not be a good idea to keep crayfish with anybody in the tank. Of course, we can find some examples where people managed to keep aggressive species together.