What Do Lobsters Eat? Wild vs. Pet Freshwater Lobster Diets

If you've landed here wondering what lobsters eat, you're probably either curious about the ocean creature on your dinner plate, or you're a fish keeper eyeing one of those colorful "freshwater lobsters" at the pet store. Both questions have real answers, and they're not the same animal. This guide covers both, so you get accurate info no matter which lobster brought you here.

Quick Answer: True ocean lobsters are scavengers that eat fish, mollusks, worms, and algae on the seafloor [1]. Pet "freshwater lobsters" are actually crayfish, and they thrive on a mix of sinking pellets, blanched vegetables, and occasional protein like frozen shrimp. Both groups need calcium-rich food to rebuild their shells after molting.

What Do Wild Lobsters Actually Eat?

Wild lobsters are opportunistic scavengers that eat almost anything they can catch or find on the ocean floor. Their diet includes fish, crabs, mussels, sea urchins, and even other lobsters when food is scarce [1]. They use their strong claws to crush shells and their smaller front legs to tear food apart.

Lobsters hunt mostly at night. They rely on smell more than sight, using tiny sensory hairs on their legs and antennae to track food from far away.

• Small fish and fish scraps
• Clams, mussels, and snails
• Crabs and other crustaceans
• Sea urchins and starfish
• Algae and plant matter, especially as juveniles

According to NOAA Fisheries, lobsters are important scavengers that help keep ocean floor ecosystems balanced [1]. Without them, dead fish and shellfish would pile up faster than the ecosystem can process.

Are "Freshwater Lobsters" Real?

Yes, but they're not true lobsters — they're crayfish, usually sold under names like "Australian Red Claw Lobster." The confusion comes from marketing, not biology. True lobsters are saltwater animals and cannot survive in a home aquarium long-term.

The species most often labeled a "freshwater lobster" is Cherax quadricarinatus. It's a large, hardy crayfish popular in the aquarium hobby for its size and color. If you're setting up a tank for one, check out this 20 gallon tank guide for a solid starting point on space and filtration.

Pro Tip: Always ask the pet store for the scientific name before buying. "Lobster" on the label almost always means crayfish, not a true marine lobster.

What to Feed a Pet Freshwater Lobster (Crayfish) in Your Tank

Pet freshwater lobsters need a varied diet of sinking pellets, blanched vegetables, and occasional protein. They're omnivores, just like their wild ocean cousins, and they'll eat almost anything that lands on the tank floor. A one-note diet leads to poor shell health over time.

Good staple foods include:

• Sinking shrimp or bottom-feeder pellets
• Blanched zucchini, carrots, or spinach
• Freeze-dried or frozen shrimp and bloodworms
• Algae wafers
• Cuttlebone or calcium chips for shell strength

A sinking pellet food for bottom feeders works well as the daily base, since it sits where the lobster actually lives instead of floating out of reach.

Crustacean nutrition research consistently links dietary calcium to faster, safer shell recovery after molting [2]. Skipping supplements can leave a lobster's new shell soft and vulnerable to injury.

How Often and How Much to Feed Your Tank Lobster

Feed adult freshwater lobsters once a day, and only what they can finish in about two hours. Overfeeding is one of the most common mistakes new keepers make, since leftover food fouls the water fast.

Juveniles under 3 inches long can eat small amounts twice daily to support faster growth. Adults over 4 inches do fine with one feeding session.

Pro Tip: If you're new to keeping crayfish, start with our beginner-friendly 20 gallon tank guide to get filtration and space right before you bring one home.

Remove uneaten food within a few hours. Rotting food spikes ammonia, and ammonia is far more dangerous to a lobster than a skipped meal.

Common Feeding Mistakes That Hurt Your Lobster

The biggest mistake keepers make is feeding only protein and skipping calcium and fiber. A protein-heavy diet speeds up growth, but it also weakens the shell and shortens lifespan.

Common Myth: "Lobsters can eat anything, so leftovers from your dinner are fine." Reality: Seasoned, fatty, or salty human food can damage a crayfish's digestive system and pollute tank water fast [2].

Other mistakes to avoid:

• Feeding too much at once, which fouls water quickly
• Ignoring calcium after a molt, leading to soft or deformed shells
• Skipping vegetables entirely, which causes constipation over time
• Using tap water with heavy metals, which stresses molting lobsters

A calcium and mineral supplement block placed in the tank gives your lobster a way to self-regulate its calcium intake between feedings.

Tank Size, Setup, and Mates for a Pet Lobster

Freshwater lobsters need at least 20 gallons of tank space, and more room reduces aggression toward tank mates. They're territorial and will fight, injure, or eat smaller fish given the chance.

Consider these setup basics:

• Minimum 20 gallons for one adult; see this 30 gallon tank guide if you want extra room to grow
• Sand or fine gravel substrate for burrowing
• Hiding spots like caves or PVC pipe to reduce stress during molting
• Secure lid, since crayfish are surprisingly good climbers

Need to keep costs down on your first setup? See our budget-friendly tank picks →

Do Wild and Farmed Lobsters Eat the Same Food as Pets?

No — wild and farmed marine lobsters eat a much more protein-heavy, fish-and-shellfish-based diet than pet freshwater lobsters. Aquaculture operations raising true lobsters for food formulate feed around growth speed and shell yield, not long-term pet health [3].

As of August 2026, most lobster aquaculture research still centers on growth rate and survival in commercial settings, not aquarium care [3]. That's part of why hobbyist "freshwater lobster" (crayfish) diets look so different from what you'd read about Maine lobster farming.

Studies on crustacean molting cycles show that diet quality directly affects how successfully an individual survives each molt [2]. That finding holds true whether you're talking about a wild ocean lobster or a crayfish in a home tank.

Ready to bring home your first freshwater lobster? Start with our beginner tank setup checklist →

Conclusion

True lobsters and pet "freshwater lobsters" eat similar categories of food — protein, plant matter, and calcium — but in very different proportions and settings. Wild lobsters scavenge fish and shellfish on the ocean floor [1], while pet crayfish do best on a rotation of sinking pellets, blanched veggies, and occasional protein with steady calcium support. Get the ratio right, and your tank lobster will molt safely and live for years.

Sources

1. https://www.fisheries.noaa.gov/national/outreach-and-education/fun-facts-about-luscious-lobsters
2. https://pubmed.ncbi.nlm.nih.gov/19347157/
3. https://pmc.ncbi.nlm.nih.gov/articles/PMC9454674/