Scarlet hermit crab reef compatibility check
Paguristes cadenati
Scarlet hermit crab (Paguristes cadenati) is a beginner-level hermit crab that needs at least 10 gallons. It is reef safe with caution; still may disturb snails or frags despite a calmer reputation. Temperament varies and adults reach about 1.5 inches.
Common cleanup crew hermit that works best in modest numbers.
Who it is for
Good fit for
- ✓ Tanks of 10+ gallons at the animal's adult size.
- ✓ Beginners following a slow, planned stocking order.
- ✓ Newly cycled tanks with a compatible stocking list.
Not a fit for
- ✕ Tanks under 10 gallons, even while it is small.
- ✕ Reefs where the cautions on this page would put existing corals or inverts at risk.
- ✕ Still may disturb snails or frags despite a calmer reputation.
Compatibility warnings
- Still may disturb snails or frags despite a calmer reputation.
- Check adult size against the final tank, not the fish or coral at purchase size.
- Add livestock slowly so the bioload and nutrient export can keep up.
- Use the planner when this animal changes the tank-size, flow, lighting, or stocking plan.
Professional planning context
- Use the 10 gallon minimum as an adult-planning floor; display length, aquascape, and existing tankmates can raise that floor.
- This can be planned early after cycling, but only after quarantine/acclimation logistics and stocking order are settled.
- Invert plans should account for copper exposure, acclimation sensitivity, predation risk, and whether the tank can actually feed the animal.
Tank fit and maturity gate
ReefCrafter uses 10 gallons as the planning floor for adult size, swimming room, nutrient load, and aggression margin.
This species can be planned early when the tank is cycled and the rest of the stocking list is compatible.
Care notes
- Temperament
- Varied
- Reef safety
- Caution
- Adult size
- 1.5 in
- Placement
- Build dependent
- Diet
- Build dependent
- Flow
- Varied
- Light
- None
- Bioload
- 0.1
- Stocking stage
- Middle
Related species
- Blue leg hermit crab
Same 10-gallon floor.
- Feather duster worm
Same 10-gallon floor, intermediate care, reef safe.
- Harlequin shrimp
Same 10-gallon floor, expert care, reef safe.
- Nassarius snail
Same 10-gallon floor, reef safe.
Equipment that fits
- Innovative Marine 20 NUVO Fusion Peninsula PRO 2 AIO Aquarium with APS Pedestal
20-gallon display, above this animal's 10-gallon floor.
- Innovative Marine 10 NUVO Fusion PRO 2 AIO Aquarium Bundle
10-gallon display, above this animal's 10-gallon floor.
- Ultum Nature Systems UNS 60S Ultra Clear Rimless Aquarium
10-gallon display, above this animal's 10-gallon floor.
Related reading
Questions
What size tank does the scarlet hermit crab need?
ReefCrafter plans for at least 10 gallons, based on an adult size of about 1.5 inches, plus room to forage and the stability a larger water volume gives. Use the adult size, not the size at purchase.
Is the scarlet hermit crab reef safe?
It is reef safe with caution in ReefCrafter's catalog. Watch for: Still may disturb snails or frags despite a calmer reputation.
Is the scarlet hermit crab good for beginners?
Yes. It is rated beginner care.
When should I add the scarlet hermit crab to my tank?
ReefCrafter treats it as middle-stage livestock, with no tank-age gate beyond a finished cycle. Add livestock slowly so nutrient export keeps up.