The Complete Guide to Keeping Porcelain Crabs

Porcelain Crabs (family Porcellanidae) are delicate, filter-feeding marine crustaceans admired for their intricate patterns, fan-like feeding appendages, and peaceful nature. Despite their crab-like appearance, they are more closely related to squat lobsters and are a fascinating addition to well-maintained reef aquaria. Native to tropical and subtropical oceans worldwide, they are most commonly found living amongst rocks, corals, and anemones.

When kept in suitable conditions, Porcelain Crabs are hardy, low-impact, and highly rewarding for aquarists interested in naturalistic marine behaviour.

What Are Porcelain Crabs?

Porcelain Crabs are small, flat-bodied crustaceans known for their fragile exoskeletons and specialised filter-feeding behaviour. They use feathery appendages (called maxillipeds) to catch microscopic food particles from the water column.

They are:

• Small: Typically 2–5 cm across depending on species

• Fully marine: Require stable saltwater conditions

• Peaceful: Non-aggressive and reef-safe

• Filter feeders: Rely on suspended food rather than scavenging

Their name comes from their delicate, porcelain-like appearance and tendency to shed limbs easily when stressed.

Enclosure Requirements

Aquarium Size

Porcelain Crabs can be kept in relatively small systems, with a minimum of 60 litres recommended. However, larger aquaria (100+ litres) are ideal, as they provide more stable water conditions and a consistent supply of suspended food.

They are best suited to established reef tanks rather than newly set-up systems.

Marine Aquarium Setup

Porcelain Crabs thrive in mature marine aquaria with stable conditions and active water flow.

Ideal setup includes:

• Live rock with crevices and overhangs

• Moderate to strong water movement

• Established biological filtration

• Optional hosting anemone (species dependent)

They do not require any land access and remain fully aquatic.

Substrate

Substrate is not particularly important for Porcelain Crabs, as they spend most of their time perched on rocks or within crevices.

Suitable options include:

• Fine aragonite sand

• Coral sand

• Bare-bottom setups

The key focus should be on rock structure rather than substrate type.

Water Conditions

Stable and high-quality water is essential.

• Salinity: 1.024–1.026 specific gravity

• Temperature: 24–26°C

• pH: 8.0–8.4

• Alkalinity: 8–12 dKH

• Ammonia/Nitrite: 0 ppm

• Nitrate: <10 ppm

Consistency is more important than chasing exact numbers. Regular water changes (10–20% every 1–2 weeks) are recommended.

Filtration and Flow

Porcelain Crabs rely heavily on water flow to feed.

• Moderate to strong, indirect flow is ideal

• Protein skimmer recommended

• High oxygenation is beneficial

Avoid placing them in areas of excessively turbulent flow where they cannot remain anchored.

Lighting

They have no strict lighting requirements.

• Standard reef lighting is sufficient

• Often hide during bright periods

• More active in lower light

Lighting primarily supports the overall reef ecosystem rather than the crab directly.

Decor and Hiding Spots

Porcelain Crabs require secure perching spots and shelter.

Provide:

• Rock crevices and ledges

• Overhangs with steady flow

• Small caves for protection

Some species form symbiotic relationships with anemones, particularly Neopetrolisthes species, which may live amongst anemone tentacles for protection.

A complex aquascape reduces stress and encourages natural behaviour.

Diet and Feeding

Porcelain Crabs are specialised filter feeders and do not graze like typical crabs.

Natural Diet:

• Plankton

• Suspended organic particles

• Microalgae and detritus

Supplemental Feeding:

• Phytoplankton (live or bottled)

• Zooplankton products

• Reef roids or similar fine coral foods

• Finely crushed frozen foods (e.g. mysis, brine shrimp)

Feed small amounts regularly (3–5 times per week) to ensure a constant supply of suspended food. Target feeding upstream in the water flow works well.

Without adequate feeding, they may slowly starve despite appearing active.

Behaviour and Reef Safety

Porcelain Crabs are among the most reef-safe crustaceans.

Typical behaviour:

• Perching in high-flow areas

• Continuously “fanning” for food

• Retreating quickly when disturbed

Key traits:

• Non-aggressive

• Do not harm corals or fish

• May defend a small territory from other Porcelain Crabs

They are fragile and can drop limbs as a defence mechanism, though these will regrow over time.

Tank Mates

Porcelain Crabs are compatible with a wide range of peaceful marine species.

Suitable tank mates:

• Small reef fish (e.g. clownfish, gobies)

• Snails and other clean-up crew members

• Shrimp (cleaner, peppermint)

• Corals and anemones

Avoid:

• Aggressive fish (triggers, large wrasses, puffers)

• Predatory crabs

• Larger invertebrates that may harass them

Care should be taken to ensure they are not outcompeted for food.

Moulting

Like all crustaceans, Porcelain Crabs moult as they grow.

During moulting:

• They may hide for several days

• Their body becomes soft and vulnerable

• A shed exoskeleton may be mistaken for a dead crab

To support moulting:

• Maintain stable water parameters

• Ensure adequate nutrition

• Provide safe hiding spaces

Do not remove the moult immediately, as it may be consumed for calcium and minerals.

Breeding

Breeding Porcelain Crabs in captivity is rare and challenging.

• Females carry eggs beneath their abdomen

• Larvae are planktonic and require specialised conditions

• Survival rates in home aquaria are extremely low

Most specimens in the aquarium trade are wild-caught.

Common Health Issues

Porcelain Crabs are relatively hardy when properly cared for but are sensitive to stress.

Watch for:

• Loss of limbs (often stress-related)

• Reduced feeding activity

• Hiding excessively

• Failed moults

Poor water quality, insufficient feeding, and aggressive tank mates are the most common causes of issues.

Lifespan and General Care

• Lifespan: 2–4 years in captivity

• Activity: Semi-hidden but active feeders

• Maintenance: Stable parameters, regular feeding, gentle flow

They are best suited to aquarists who can provide consistent feeding and a mature system.

Conclusion

Porcelain Crabs are elegant, peaceful, and highly specialised invertebrates that bring a unique dynamic to reef aquaria. Their constant filter-feeding behaviour and delicate appearance make them particularly fascinating to observe.

While not as robust or versatile as typical clean-up crew crabs, they excel in stable, well-fed reef systems where their needs can be properly met. With the right care, Porcelain Crabs are a rewarding and visually captivating addition to any marine aquarium.