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We hope you are ready to learn about the amazing Harlequin Shrimp in this care guide. This shrimp is quite popular and you will soon know why.

This guide will teach you lots of information about these shrimp; from its unusual diet to the best way of paring them in tanks!  

Species Summary

Harlequin Shrimp, known scientifically as Hymenocera picta, are sometimes called Clown Shrimp or Painted Shrimp. They are a unique carnivorous species that adds a dazzling visual component to aquariums while displaying predatory behaviors that are remarkable to observe.

Unlike most shrimp, who scavenge their food, Harlequins are skilled hunters that feast only on starfish. Not only are they naturally adapted to be immune from the toxins released by their prey, but some marine biologists speculate that they absorb the poison and use it to ward off the fish and crustaceans that hunt them.

These geographically dispersed shrimp live in the warm waters across the Indian and Pacific Oceans. Reef divers find Harlequins off the coast of east Africa, Australia, Hawaii, Indonesia, Panama, and the Galapagos Islands. Harlequin Shrimp stick to crevices and caves where they can hide between hunting expeditions.

Wild Harlequins keep within 100 feet of the surface an established and well-defined territorial boundary with other shrimp. Scientists have observed complex social relationships between mated pairs of Harlequins, who bond for life. They hunt prey and fight predators together.

Appearance

Harlequin shrimps are one of the most striking members of the crustacean family. They are cream-colored with brownish-orange to bright pink spots outlined with blue edges. They have the somewhat amorphous shape of most other shrimp species and long skinny legs relative to their body size. They differ from their relatives because their claws and eyes are flatter.

Harlequins have two leaf-shaped sensory antennules near their eyes used to smell and locate their prey. Males are generally considered more agile and effective hunters. The underside of the shrimp features eight pereiopods, legs used to crawl along coral and rock. They also have ten pleopods, forked limbs used for swimming, across their abdomen.

You may see Blue Harlequin Shrimp when shopping for your tank. They have the same shape and cream color as the common Harlequin Shrimp but feature blue spots outlined with yellow edges. These shrimp mostly live in the Indian Ocean. Biologists are still debating whether the Blue Harlequin is a separate species or a subspecies of Harlequin Shrimp.

Lifespan

With proper care and consistently maintained aquarium conditions, the average Harlequin Shrimp lifespan could be up to seven years. Experts consider they require an intermediate level of care. Though tank conditions must be precise, once you master feeding them and provide adequate space to hide, they will generally thrive. The main burden with keeping Harlequins is the cost of securing their food and cleaning their tanks.

Average Size

Understanding the size Harlequin Shrimp is of importance to many aquarium owners because the bigger the shrimp the bigger the cost. They can reach up to 2 inches in length and only weigh a few ounces with females being slightly bigger than males.  So depending on your preference you might decide to spend some extra money to have a big looking shrimp or save some and start raising a young shrimp.  

Harlequin Shrimp Care

To properly care for a Harlequin Shrimp you would need to observe its behavior, effectively monitor its diet and routinely surveil of your tank conditions.

Tank Size

Your Harlequin Shrimp requires a 10-gallon or larger tank. They will spend their time among the rocks and coral. Their size, striking color pattern, and active nature ensure they stand out regardless of the tank size. Experts recommend a 20-gallon or larger tank if you house a pair of shrimp. The main challenge of keeping shrimp in smaller tanks is maintaining proper water conditions for their survival.

Author Note: Harlequin Shrimp are relatively poor swimmers and weak crawlers, therefore, they cannot tolerate fast currents. These shrimp will keep to the coral and rubble, emerging to feed before returning to their shelter.

Water Parameters

• Water temperature: 72°F to 82°F
• pH levels: pH must stay between 8.0 and 8.4
• Water hardness: keep between 8 and 12 dKH
• Specific gravity: Salinity is best between 1.023 and 1.025 sg

Like other crustaceans, Harlequin Shrimp are vulnerable to ammonia, nitrite, and nitrate produced by nitrogenous waste. Maintaining 0 ppm of these compounds gives your shrimp the best chance to thrive.

What To Put In Their Tank

When aquascaping, it’s crucial to simulate your Harlequin’s natural habitat and account for its behaviors. While it may seem counterintuitive, providing ample hiding spaces using caves, rocks, and crevices will make your shrimp easier to spot.

If they feel secure, with comfortable hiding spots, the shrimp will be more adventurous and explore the tank. Without cover, the shrimp’s defense impulses kick in, driving it into continual hiding. Not only will this stop you from enjoying your shrimp, but it will deprive them of food because they will be too tentative to hunt and feed.

Author Note: Artificial plants and hollow plastic constructs like ships are all acceptable. Your shrimp will explore rock and coral without causing harm. If you plan to keep a pair of shrimp, be sure to provide a hiding spot that’s large enough to house both Harlequins.

Common Possible Diseases

While not vulnerable to any particular diseases, Harlequin Shrimp are extremely sensitive to even minute alterations in tank conditions. It’s essential to remove molted shells, dead fish, the carcasses of starfish, and anything else that can decompose and release ammonia or nitrates.

In addition, these shrimp cannot tolerate even trace amounts of copper. Be sure to verify the content before adding anything to your tank.

Food & Diet

Biologists consider this shrimp a specialty predator because they are so well adapted to hunting and devouring a specific prey, starfish. In fact, you will find many videos and articles of Harlequin Shrimp eating starfish since they will reject any other food you offer. Purchasing starfish or maintaining a population is the main challenge in raising and keeping Harlequins. Fortunately, they will eat virtually any species of starfish.

Harlequins will consume live or frozen and thawed starfish. Defrosted food decays faster, so monitor how quickly the shrimp consumes the starfish. Depending on the size of your shrimp, a 4″ to 6″ diameter starfish can provide up to one month’s nourishment because the starfish regenerate and the shrimp devour them slowly. Chocolate chip starfish, which cost about $9 to $12, are the most cost-effective food source.

Providing adequate hiding spaces is vital because the shrimp will drag its prey to its cave to feed.

Author Note: It’s essential to monitor the shrimp’s food intake. Once the starfish dies, its remains must be removed from the tank immediately to prevent a harmful buildup of ammonia and other nitrogenous waste.

You can also isolate a starfish in a separate tank and remove its limbs to feed your Harlequin fish. In the wild, starfish detach their limbs as a defense mechanism. Shrimp have adapted to eating the appendages.

Beyond their beauty and fascinating behaviors, Harlequin Shrimp’s food preference also helps with parasite control. Asterina starfish are a common inhabitant of reef tanks that gain access as passengers in rocks and other items you add to your tank.

Unmanaged, your reef might become compromised since starfish feed on coral and they can easily multiply themselves. Fortunately, your Harlequin is a skilled hunter who will consume Asterina, preserving your tank’s beauty while reducing its consumption of the starfish you provide. This service saves your tank while reducing feeding costs. You can also grow a colony of Asterina in a separate tank to use as food.

Behavior & Temperament

Observing their unique behaviors is one of the greatest joys of keeping Harlequin Shrimp. While an aggressive hunter of starfish, these shrimp are docile with fish and invertebrates. They will comb the tank coral and generally do better when kept as a mated pair.

Harlequins are only territorial and aggressive with other species of shrimp and Harlequin Shrimp of the same sex. Keeping two males or two females will lead to aggression. Males have been documented fighting to the death. A bonded pair of Harlequins will function closely together. They stay side by side for defense while cooperatively hunting starfish.

Beyond their hunting activities, you will also observe your Harlequin’s molting process. Like all shrimp, they have an exoskeleton that houses their soft body. As the shrimp grows, they develop a new exoskeleton to accommodate their increased size and shed their old ones. You’ll be able to watch your shrimp emerge from its old shell like a butterfly escaping a cocoon.

The new exoskeleton is soft when it first develops, so your shrimp will spend more time hiding in its cave during the first few days after molting to allow its shell to harden.

Harlequin Shrimp Tank Mates

Breeding

Harlequin Shrimp pairs best when they are mixed-sex because they will breed and work together to hunt. When identifying shrimp, you must look under their tails. Males are spotless. Females have the same spotted color pattern that covers the rest of their bodies.

Females reach sexual maturity at 200 to 240 days old. They will spawn after each subsequent molt, usually every 18 to 26 days.

Once pregnant, the female Harlequin will carry the fertilized eggs under her abdomen, a process called “berrying.” The shrimp will hold onto the eggs for two to three weeks, using her tail as a fan to oxygenate the eggs. Two or three days before hatching, the eggs turn translucent and the female stops eating.

Author Note: At this point, you should transfer both shrimp to a separate tank with the same conditions as their home tank. Keeping the parents together reduces stress on each shrimp.

Once released, the eggs are microscopic and grow during a five to six week planktonic phase. The parents can return to their tank once the females release the eggs. Eventually, the plankton develops into shrimplets that will crawl about the tank.

The shrimp will feed on green water algae and rotifers through their planktonic phase before transitioning to shrimp nauplii as they grow.

Wrapping Up

As you can see, this shrimp is quite interesting not only for its nice looking shape and colors but for its not so usual diet and temperament.

The aforementioned is probably the reason why they are so popular not only among our many care guides but among many other shrimp enthusiasts. 

If you own a Harlequin Shrimp we’d love to hear some stories from you. We’ve heard so many great stories about this shrimp over the years, and we think it would be fun to start including some in our guide.