Thenus spp. - Slipper Lobster

The designation Thenus spp. means that the exact species may vary. The genus includes several similar flathead slipper lobsters, including Thenus orientalis, Thenus australiensis, Thenus indicus and related species.

Unlike conventional lobsters, Thenus species do not have large claws. Their second pair of antennae has developed into broad flattened plates used for sensing, digging and protection.

The lobster spends daylight hours beneath rock ledges, inside large caves or partially buried in sand. It emerges after the aquarium lighting dims to search for food.

Key features

• Flattened marine lobster
• Scientific identification: Thenus spp.
• Common names: Slipper Lobster and Flathead Lobster
• Family: Scyllaridae
• Exact species may vary
• Broad shovel-shaped antennae
• No large claws
• Armoured, sand-coloured body
• Primarily nocturnal
• Partially buries in sand
• Requires extensive bottom area
• Requires stable rockwork
• Primarily carnivorous
• Preys on molluscs and crustaceans
• Not a clean-up-crew animal
• Not reliably reef safe
• May overturn corals and move rocks
• May reach a substantial adult size
• Requires powerful filtration
• Sensitive to copper-based medications
• Requires a secure aquarium cover
• Recommended for experienced marine aquarists

Care information

• Scientific identification: Thenus spp.
• Family: Scyllaridae
• Animal group: decapod crustaceans
• Adult size: commonly approximately 20–30 cm, depending on species
• Diet: marine animal foods and benthic invertebrates
• Activity: primarily nocturnal
• Temperament: generally peaceful but predatory toward smaller animals
• Reef compatibility: not recommended for conventional reef aquariums
• Care level: intermediate to advanced
• Natural habitat: sandy and muddy seabeds
• Recommended minimum aquarium volume: approximately 400–500 litres
• Preferred substrate: fine marine sand
• Secure cover: essential

Suggested water conditions

• Temperature: approximately 22–26 °C
• Specific gravity: approximately 1.023–1.026
• pH: approximately 8.1–8.4
• Alkalinity: approximately 8–12 dKH
• Calcium: approximately 400–450 mg/l
• Magnesium: approximately 1,250–1,400 mg/l
• Ammonia: 0 mg/l
• Nitrite: 0 mg/l
• Flow: low to moderate
• Oxygenation: high

Feeding

Offer a varied selection of:

• Mussels
• Clam meat
• Shrimp
• Krill
• Squid
• Mysis shrimp
• Marine fish
• Sinking crustacean pellets

Feed after the lighting dims, generally two to four times weekly depending on size and activity. Remove uneaten food within a few hours.

Compatibility

Slipper lobsters may consume:

• Marine snails
• Bivalves
• Cleaner shrimp
• Hermit crabs
• Small crabs
• Tubeworms
• Small starfish
• Very small or sleeping fish

Avoid housing them with triggerfish, puffers, large predatory wrasses, octopuses and other animals that prey on crustaceans.

Introduction

1. Determine the exact species and previous holding temperature whenever possible.
2. Confirm that the aquarium is fully established.
3. Stabilise all rockwork before introduction.
4. Provide a large cave and extensive sandy area.
5. Seal all potential escape routes.
6. Dim the aquarium lighting.
7. Acclimate gradually to temperature and salinity.
8. Do not lift the animal by its antennae or legs.
9. Transfer it underwater in a sturdy container.
10. Place it on sand close to a suitable shelter.
11. Do not force it into a rock crevice.
12. Offer the first small meal after the animal becomes active.
13. Avoid all copper-based medications.