Mantis shrimp are enthusiastic, aggressive eaters that thrive on a diet of meaty seafood offered every two to three days. What you feed depends largely on whether you have a “smasher” or a “spearer” species, since each hunts differently and prefers different prey. Most captive mantis shrimp do well on a mix of live and frozen shellfish, crustaceans, and fish.
Smashers vs. Spearers: Diet Differences
There are over 400 species of mantis shrimp, broadly split into two groups based on how they catch food. Smashers have club-like appendages that generate incredibly forceful strikes to crack open hard-shelled prey. A single smasher feeding on a snail can deliver an average of over 70 strikes, strategically working from the shell opening to the tip to maximize damage. Spearers, by contrast, have barbed, spear-like appendages designed to impale soft-bodied prey.
This distinction shapes what you should offer. Smashers want hard targets: snails, clams, hermit crabs, scallops, and other shelled animals they can break apart. Spearers prefer softer prey like small fish and shrimp. If you’re unsure which type you have, the shape of the front appendages is the giveaway: rounded clubs mean smasher, pointed spines mean spearer.
Best Foods for Captive Mantis Shrimp
Live Food
Live prey is the gold standard for mantis shrimp because it encourages natural hunting behavior and keeps the animal mentally stimulated. Good live options for smashers include hermit crabs, emerald crabs, decorator crabs, arrow crabs, snails, clams, scallops, small lobsters, and shrimp. Essentially, anything with meat inside a shell that the mantis can crack open works well. For spearers, live feeder shrimp and small fish are more appropriate.
Live food does cost more and can introduce parasites or disease into your tank, so many keepers use it as an occasional enrichment rather than a staple.
Frozen Food
Frozen seafood is the practical backbone of most captive mantis shrimp diets. Cocktail shrimp, squid, krill, clam meat, and silverside chunks are all widely accepted. Silversides in particular are available at almost every local fish store. You can also buy grocery store seafood like raw shrimp, squid, and clams, as long as it hasn’t been treated with added iodine or preservatives. Cut pieces to a size your mantis can handle comfortably.
To offer frozen food, thaw it in a small cup of tank water first, then drop it near the entrance of the mantis shrimp’s burrow using tongs or a feeding stick. Most mantis shrimp will grab food aggressively within seconds. Remove any uneaten pieces after an hour or so to prevent water quality problems.
Vitamin Supplements for Frozen Diets
Frozen food loses some nutritional value during processing and storage. Many experienced reef keepers soak frozen food in a vitamin supplement before feeding. The most popular option is Selcon, a supplement rich in highly unsaturated fatty acids (HUFAs) and vitamin C. Other commonly used products include Boyd’s Vitachem, Kent Marine Zoe (which is heavy on vitamin C and other vitamins), and Brightwell’s Vitamarin line.
The process is simple: place the thawed food in a small cup, add a few drops of supplement, let it soak for 10 to 15 minutes, then feed. This is especially worthwhile if frozen food makes up the majority of your mantis shrimp’s diet, since it helps fill nutritional gaps that live prey would naturally cover.
How Often to Feed
Adult mantis shrimp do well eating every two to three days. In research settings, they’re typically fed about twice per week with frozen krill, brine shrimp, or fresh snails. Many hobbyists follow a similar schedule and report healthy, growing animals on two feedings per week.
Juveniles and smaller species may benefit from slightly more frequent feeding, roughly every other day, since they’re actively growing and burn through calories faster. Overfeeding is a bigger risk than underfeeding with mantis shrimp. Excess food fouls the water quickly in the small tanks these animals typically live in, and a well-fed mantis shrimp that suddenly stops eating is usually molting, not starving. Skip feeding for a few days if your mantis retreats to its burrow and stops responding to food.
Foods to Avoid
Don’t feed mantis shrimp anything seasoned, cooked, or preserved with chemicals. Raw grocery store seafood is fine, but check the label for added sodium tripolyphosphate or iodine solutions, which are common in packaged shrimp and can harm invertebrates. Freshwater fish and freshwater crustaceans aren’t ideal either, since the nutritional profile doesn’t match what a marine predator needs. Stick with saltwater species when possible.
Avoid relying on a single food item exclusively. A mantis shrimp fed nothing but cocktail shrimp, for example, will miss out on the calcium and other minerals it would get from cracking open snail shells or crab exoskeletons. Smashers in particular benefit from shelled prey because the act of breaking shells keeps their striking appendages exercised and provides dietary calcium that supports their own molting cycle.
Keeping Smashers Stimulated at Feeding Time
Smashers are remarkable problem-solvers, and feeding time doubles as enrichment. Offering a sealed clam or a live hermit crab gives the animal a puzzle to work through, not just a meal. You can watch the mantis shrimp systematically target weak points in the shell, rotating its prey and adjusting strike placement. This behavior is a sign of a healthy, engaged animal.
If you’re feeding frozen food, try placing it inside an empty snail shell or wedging it into a crevice in the rockwork. This forces the mantis to work for its meal and mimics the foraging challenges it would face in the wild. Varying the type and presentation of food from one feeding to the next keeps your mantis shrimp active, curious, and behaving naturally.