Slipper Lobsters (Scyllaridae) are one of the popular lobster types commonly kept as aquarium pets. These marine invertebrates are quite fascinating, unique, and eye-catching.
Though a poor choice for mixed reef tanks due to their relatively large size and relentless burrowing habits, this saltwater critter can be kept successfully in a species-only tank once optimal living conditions are made available.
This article offers valuable insights into the morphology, behavior, taxonomy, habitat, and proper captive care of Slipper lobsters.
Quick Notes about Slipper Lobsters
||Bulldozer lobster, Shovel-nosed lobster, and Sand lobster|
|Scientific Name||Arctidinae spp., Ibacinae spp., Scyllarides spp., and Theninae spp.|
|Tank size (minimum)||90 gallons (~340 liters)|
|Breeding||Difficult (Almost impossible)|
|Size||2 – 20 inches (~5 – 50 cm) (depends on the species)|
|Optimal Temperature||22 – 26°C (~72°F – 79°F)|
|Water type||SG = 1.023 – 1.025|
|Optimal PH||8.0 – 8.4|
|Optimal KH||8 – 12|
|Nitrate||Less than 10 ppm|
|Life span||up to 3 – 15 years (depends on the species)|
|Color Form||Typically brown (with different shades), reddish-brown, slightly pink, and brown tinged with yellow or orange|
Taxonomy of Slipper Lobsters
Slipper lobsters are members of the family Scyllaridae which consists of about 90 species of achelate crustaceans in the Order Decapoda. They are close relatives of the spiny lobster and furry lobsters (Palinuridae), and these three lobster groups lack the claws found on virtually all other decapods.
Scyllaridae is divided into four subfamilies:
- Arctidinae (Genera: Acrtides & Scyllarides),
- Ibacinae (Genera: Ibacus & Parribacus),
- Scyllarides (Genera: Galearctus & Scyllarus), and
- Theninae (Genus: Thenus).
Therefore, the taxonomical classification/hierarchy of Slipper lobsters is as follows:
Subfamilies: Arctidinae, Ibacinae, Scyllarides, Theninae
Note: Most species of Slipper lobsters are fit for human consumption, for example: Thenus orientalis, Ibacus Peronii, and all six species of Parribacus are edible and they form part of main dishes in certain countries.
Habitat of Slipper Lobsters
These lobsters are naturally domiciled in continental shelves, found at depths of 20 to 500 meters (66 – 1,600 feet).
Apparently, they inhabit coastal reefs and rocky bottoms in warm coastal waters in the Indo-Pacific region, and their distribution range encompasses South Carolina, Florida, Hawaii, Japan, the Philippines, New Caledonia, Mascarene Islands, Atlantic Ocean, Mediterranean Sea, Caribbean Sea, Gulf of Mexico, and the northern coast of Australia from Western Australia to Queensland.
Description of Slipper Lobsters
At a glance, the body of a Slipper lobster somewhat looks like a terrestrial insect or bug.
Being achelate crustaceans (members of the Infra-order Achelata), Slipper lobsters lack the typical large claws (chelae) found in most lobsters. Rather, their second pair of antennae are modified (enlarged and flattened) into large/wide plates which are quite fit for burrowing.
These plate-like, conspicuous antennae differentiate Scyllarids from Palinurids as well as other lobsters at large.
The first pair of antennae are for sensory perception; to help the lobster detect changes in its environment, and these are borne on long orange or yellow flexible stalks.
These lobsters have 6 segments in their heads and 8 segments in the thorax (chest area), which are collectively covered in a thick carapace. They respire by way of gills which also serve as a primary site for the excretion of ammonia.
The marine lobster has a highly flattened/depressed body and a very hard chitinous exoskeleton; built like armor.
- Arctides and Scyllarides spp. have a highly vaulted carapace, a three-segmented mandibular palp, and a shallow cervical incision along the lateral margin of the carapace.
- For Ibacus and Parribacus, the carapace is dorso-ventrally compressed with a deep cervical incision, and they possess a simple or two-segmented palp.
- In Thenus, the eyes are found embedded at the extreme ends of the carapace unlike the medial placements in other groups.
Also, species of Slipper lobsters vary considerably in size, e.g. Scyllarides haani maxes out at 50 cm (20 inches) long, Scyllarides aequinoctialis & latus are about 30 cm (12 inches) in length, Parribacus antarcticus about 20 cm (8 inches), and Scyllarus pygmaeus attaining a maximum size of 5 cm (2 inches).
In addition, they possess drab coloration, typically brown (with different shades), reddish-brown, slightly pink, and brown tinged with yellow or orange and this helps in camouflaging.
Lifespan/Longevity of Slipper Lobsters
Depending on the species, the lifespan of Slipper lobsters can range from 4 years (for example, Thenus spp.) to more than 15 years (Ibacus spp.).
Behavior of Slipper Lobsters
They are nocturnal, thus it’s common for these inverts to rest throughout the day, then emerge from the shelters at night to seek out prey or edible food items to consume.
These animals have two modes of movement:
- slow walking movements within a small home range,
- swimming movements that can be used for rapid escape.
Slipper lobsters are also powerful burrowers, capable of shoveling or burrowing into the substrate bed and digging the underside of rocks. This activity may cause the rocks to shift from their normal position, hence the need to secure the rocks in your tank to prevent it from toppling over the lobster.
In response to predatory attacks, the Slipper lobster will cling firmly to the substrate using its strong legs to avoid getting dislodged, hide or conceal itself within sediments/rocks, or swim away from the radar of the predator. In worst cases, the Slipper lobster will stay put and depend on its tough carapace to protect it from the incoming assault.
Interesting fact: The clinging force can reach maximum magnitudes of 3 to 15 kg or 7 – 33 Lbs (∼8 to 29 times the bodyweight of the lobster), it linearly correlates with the lobster size
Some Slipper lobster species appear to be solitary (for example, Thenus spp.). However, even when they are held together in tanks, they display little to no interest in other individuals. Agonistic encounters only appear to arise over food items.
Feeding Slipper Lobsters
Slipper lobsters are omnivores—they will readily accept plant and animal matter.
According to the gut content analyses, these saltwater lobsters feed on a variety of food items:
- sea urchins,
- sea stars,
- sea squirts,
- fish flesh,
- polychaete worms, etc.
Their strong jaws and limbs are able to split the shells of clams, oysters, and snails for quick and easy ingestion.
In aquariums, other acceptable food items include:
- feeder fish,
- dead/decaying animal matter,
- fish food flakes and pellets.
The best time to feed Slipper lobsters is at night when they are most active.
Make sure to target-feed them using feeding prongs. This way, you would be sure that they actually eat the food items. Always provide a varied diet to stimulate good health and steady growth.
Are Slipper Lobsters Reef Safe?
The short answer is no, Slipper lobsters are not considered reef-safe due to their constant digging habits and huge sizes (evident in most species).
Do not forget that they are omnivores. So, they may start picking at your corals even when they’re given enough food.
Tank Requirements and Water Parameters
Make sure to keep this lobster in large tank setups because of its growth potential. At least, this should be an enclosure with a width twice (2x) the length of the lobster, and a length about four times (4x) the length of the lobster.
Hence, a 90 gallon (~340 Liters) tank with dimensions of 48” x 18” x 24” (L x W x H) should be suitable for housing a Slipper lobster with a maximum length of 8 inches (20 cm).
This invert needs a lot of surface area to roam, and that’s why a tank of such size is needed.
Water type, Temperature, Hardness, pH and etc.:
Temperature: The proper water temperature for keeping Slipper lobsters is between the range of 72 – 78 °F (22 – 26 °C). Availability of an aquarium heater and chiller is crucial to help keep the tank water at the appropriate temperature.
pH: A water pH range of 8.1 – 8.4 is considered ideal for Slipper lobsters.
Hardness: The saltwater thrives in moderately hard water with values between 8 – 12 dKH.
Specific gravity: Keep salinity or specific gravity level between the optimal values 1.023 – 1.05. Use quality salt mixes, buffers, and a refractometer to attain the required measure.
Calcium: 400 – 450 ppm
Magnesium: 1350 ppm
Nitrates: 5 – 10 ppm
Nitrites: 0 ppm
Ammonia: 0 ppm
Phosphates: < 0.03 ppm
Strontium: 8 – 10 ppm
Moderate illumination is adequate for tanks housing Slipper lobsters. Stick to a consistent day/night cycle and supply light for about 10 hours daily.
Since Slipper lobsters are nocturnal, do not expose the tank to direct sunlight. Using higher Kelvin lighting (14,000 to 20,000k) will make them feel comfortable and encourage daytime activity.
Too much flow is not needed for Scyllarids, therefore moderate water flow should suffice.
Substrate and Decor:
As for substrate, a sandy or sometimes, fine gravel substrate is the right substrate for Slipper lobsters since they love to borrow quite often.
Therefore, in order to allow them to perform this natural behavior, the substrate will need to be quite deep. Establishing a thick sand layer up to 6 – 8 inches (15 – 20 cm) on the bottom of the aquarium won’t be a bad idea.
When setting up the tank, make sure it has plenty of hiding places so the lobster feels secure. Additionally, endeavor to make rocks and cavework available in the tank as these help the lobster to feel more secure.
Note: Unstable rocks & décor may dislodge and topple over your lobster, so make sure to keep them properly fastened.
Caring and Keeping Slipper Lobsters
The Slipper lobster is not the best choice for those starting out in the hobby due to the little complexity involved in its care.
As I mentioned earlier, this invertebrate is not considered reef-safe due to its budding size and steady burrowing habits which may cause damage to itself alongside other tank inhabitants—therefore, it should be kept in a dedicated species-only tank.
Well, if you are hell-bent on keeping it with other animals, then you should try out surface-dwelling fish species (fish that swim in the open water). However, be cautious while stocking to prevent too much bioload.
Another thing to note if you want to keep Slipper lobsters is the essence of a stable, clean and comfortable captive environment—they appreciate pristine water conditions, ample flow, adequate food, low nitrates levels, high calcium levels, and proper alkalinity levels.
Slipper lobsters are pretty sensitive to very low concentrations of trace materials. Keep in mind that frequent swings in pH, temperature or salinity amongst others may shock your lobster and impact its health drastically.
Important: ammonia and nitrites should always be at zero. Keep nitrates as close to zero as possible as well, though a level of 10 PPM of NO3 is acceptable.
Also, carry out regular water changes with clean water and high-quality salt mixes; this can either be 20% bi-weekly or 5% weekly in a bid to replenish the depleted nutrients and keep the tank water clean by reducing the nitrates level.
Ensure that the water is well-oxygenated/aerated, in addition, employ a protein skimmer to avail significantly in filtration.
Moreover, to aid the lobster to develop a healthy hardened exoskeleton after a molt, add mineral supplements especially calcium and iodine to the aquarium water and their diet.
Do not forget that they need careful acclimation (read more about it here) as all invertebrates. Do it very slowly. In general 2 – 3 hours will be good enough. Slipper lobsters do not like swings in salinity.
Basic Tank Equipment (links to check the price on Amazon)
Molting and Slipper Lobsters
The same as any crustaceans, Slipper lobsters tend to undergo molting — shedding the old exoskeleton periodically and forming a new, larger one to contain its expanding body.
The lobster secretes a new, soft skeleton beneath the old (hard) skeleton. After a while, the old exoskeleton will split at certain points, enabling the lobster to pull out and reveal the new skeleton. Pending when this newly formed skeleton develops (hardens), the lobster will have to hide away from predators due to its vulnerable state.
Interesting fact: According to the study, in most species, females grow larger, but more slowly than males.
For more information, read my article “Crayfish and Molting Process”.
Reproduction of Slipper Lobsters
The reproductive activities of Slipper lobsters in captivity have not been duly recorded.
In the wild, a sexually mature female will signify readiness to copulate with a male using chemicals (pheromones). Next, the male will clasp and deliver sperm to the female’s genital pores—which fertilizes the eggs.
Going further, the female will aerate, clean, and guard the fertilized eggs till they hatch.
Depending on the species, females can carry around 100 000 eggs on their enlarged, feathered pleopods. The eggs develop from an early stage to an advanced stage in 14–30 days – being a bright orange color to a dark brown before being shed into the water.
When the fertilized eggs (embryos) hatch, they will undergo series of developmental phases as planktonic, phyllosoma larvae. During this period, they sustain themselves by conducting raptorial feeding—utilizing their pereiopods to capture food items; these are then shredded by the maxillipeds and chewed by molar processes of the mandibles.
After about nine months, the larvae will molt into highly specialized nistos and proceed to settle in the deep water— before transitioning to adults.
Slipper Lobsters and Suitable Tank mates
Let me stress it again, that Slipper lobsters are not completely safe and peaceful with other tank mates. DO NOT believe pet stores that say otherwise. Their legs are so strong and claws are so sharp that they can pierce and tear apart the prey.
Unfortunately, they can become more aggressive the older and bigger they get. So, it is risky to house Slipper lobsters with:
- small and peaceful bottom fish,
- shrimp (Peppermint shrimp, Red Fire shrimp, Skunk Cleaner Shrimp, Camel shrimp, etc.),
- hermit crabs (Halloween hermit crabs, Blue Leg Hermit Crabs, etc.),
- snails (Cerith Snails, Bumble Bee Snails, Conch snails, Nassarius snails, etc.). As they will likely begin to prey on them eventually.
Even small crabs can be on their menu! They will eat whatever they can catch.
Therefore, I would not risk keeping Slipper lobsters in the community tank or simply be ready for some losses.
In essence, I am saying you’d be doing no harm by keeping Slipper lobsters alone.
Buying Slipper Lobsters
Few species of Slipper lobsters can be found in the aquarium trade, these include:
- Spanish Slipper lobster (Scyllarides aequinoctialis),
- Ridgeback Slipper lobster (Scyllarides haani),
- Vermilion Slipper lobster (Scyllarides delfosi),
- Regal Slipper lobster (Arctides regalis),
- Japanese fan lobster (Ibacus ciliatus) and
- Sculptured Slipper lobster (Parribacus antarticus).
The cost of a juvenile Slipper lobster ranges from $20 to $50, and it can be obtained at local fish stores as well as online stores that stock reef pets.
When buying Slipper lobsters, look out for healthy specimens— these should have all body parts (antennae, carapace, limbs, and tail) intact. Also, it would be in your best interest to avoid lethargic or sick specimens if you desire longevity.
It is recommended to transport Slipper lobster in a darkened confining container to reduce the stress. Don’t feed immediately after introducing them to their new home. Wait for a few days before that.
The weird appearance—modified antennae shaped like wide plates, and likeness to a terrestrial bug are what piqued my interest about the Slipper lobster.
This marine lobster is suitable for aquarium keeping, but you need to house it solely in a species-only tank to avert hassles. There are not many compatible tankmates for this lobster, though it can be kept with reef compatible, free-swimming fish e.g. Chromis.
Slipper lobsters will thrive for long in your aquarium, provided that you put in due effort to care for them properly. To this end, you need to keep pristine water conditions and ensure that they are well-fed all the time. In all other cases, they simply are not suited to the average home aquarium.