Scarlet Hermit Crab

Paguristes cadenati

(22 Reviews)

Scarlet Hermit Crab

Scarlet Hermit Crab

Paguristes cadenati

(22 Reviews)

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Scarlet Hermit Crab Care Facts

Care Level: Easy
Temperament: Peaceful
Diet: Omnivore
Reef Safe: Yes
Minimum Tank Size: 5 Gallons
Max Size: 1 inch

Scarlet Hermit Crab

The Scarlet Hermit Crab, known for its striking red body and legs, is an invaluable addition to marine aquariums, diligently scavenging detritus and aerating sand beds. Originating from the Western Atlantic Ocean, these hardy crabs thrive in shallow reef environments. They typically grow to 1 to 2 inches in shell length and have a slow but steady growth rate in captivity. Feeding them is straightforward, as they eagerly consume algae, detritus, and various foods, contributing to the tank's cleanliness.

Scarlet Hermit Crabs are compatible with Nassarius and Astrea snails, Peppermint Shrimp, Blue Leg Hermit Crabs, and Clownfish, fostering a diverse ecosystem. To ensure their well-being, provide a tank of at least 5 gallons with stable water conditions and gentle to moderate water flow. Sourcing from guarantees high-quality, healthy specimens, enriching your aquarium's biodiversity and maintaining its vibrancy.


The Scarlet Hermit Crab (Paguristes cadenati) hails from the Western Atlantic Ocean and is commonly found in shallow reef environments and intertidal zones. These hardy hermit crabs are well adapted to life on the ocean floor, and they play a vital role in keeping the substrate clean by scavenging for food and detritus.

Size and Lifespan

Scarlet Hermit Crabs are relatively small, typically growing to a maximum size of about 1 to 2 inches in shell length. In captivity, they have a lifespan of several years, making them a long-lasting and engaging addition to your marine aquarium. Regardless of size, they are voracious cleaners.

Slower Growth Rate

The growth rate of Scarlet Hermit Crabs is relatively slow and steady. Diet, water conditions, and shell availability influence their growth. With proper care, they can gradually increase in size over the years.

Dietary Needs in Captivity

Providing a balanced diet that includes marine pellets, algae wafers, and occasional meaty foods like brine shrimp or fish flakes is recommended to keep them healthy.

Compatibility with Other Fish and Invertebrates

  • Nassarius Snails (Nassarius spp.): These burrowing snails help stir and aerate the substrate while scavenging for detritus, making them suitable companions for Scarlet Hermit Crabs.
  • Astrea Snails (Astrea spp.): These snails are efficient algae grazers, contributing to maintaining a clean and algae-free aquarium.
  • Peppermint Shrimp (Lysmata wurdemanni): Peppermint shrimp are known for their ability to control pest anemones in your tank while coexisting peacefully with Scarlet Hermit Crabs.
  • Blue Leg Hermit Crab (Clibanarius tricolor): These hermit crabs share similar care requirements with Scarlet Hermit Crabs and can be added for variety.
  • Clownfish (Amphiprioninae): Clownfish often form symbiotic relationships with Scarlet Hermit Crabs, seeking refuge within their shells.

Tank Requirements

To ensure the well-being of your Scarlet Hermit Crabs, it's essential to provide the following tank conditions:

  • Minimum Aquarium Size: A suitable tank for Scarlet Hermit Crabs should have a capacity of at least 5 gallons, providing ample space for a small group of these crabs.
  • pH: Maintain a stable pH level between 8.1 and 8.4.
  • Salinity: Keep salinity levels stable at 1.023 to 1.025.
  • Water Temperature: Maintain a temperature range of 72-78°F (22-26°C).
  • Number of Scarlet Hermit Crabs per 10 Gallons: Typically, you can house 5-10 Scarlet Hermit Crabs per 10 gallons of tank capacity.

Water Flow

Gentle to moderate water flow is recommended to replicate their natural habitat conditions and ensure efficient nutrient distribution.

Other Common Names

The Scarlet Hermit Crab is also known as the "Red Leg Hermit Crab" due to the distinctive red coloration of its legs.

Reviewed by: Michael Azoury on June 5, 2024

Reviewed by: Bryan Steele on May 21, 2024

Very bright legs, stands out from the rest

Reviewed by: Keith Blair on April 10, 2024

Reviewed by: David Schneider on March 12, 2024

Reviewed by: Eric Bell on March 3, 2024

Reviewed by: David Schneider on Feb. 19, 2024

Acclimated well. Working on algae.

Reviewed by: Jerry Albright on Jan. 29, 2024

They were healthy and hungry once acclimated.

Reviewed by: Sean Boyer on Jan. 16, 2024

Non stop eaters. Does their job well.

Reviewed by: Dale Pichelmayer on Dec. 12, 2023

Running allover tank

Reviewed by: Alvin Barbes on Nov. 6, 2023

Reviewed by: Gary Vice on Sept. 28, 2023

Arrived live and well

Reviewed by: Victor Paulino on Sept. 27, 2023

Reviewed by: Richard Walker on Sept. 27, 2023

Did their thing very well

Reviewed by: Alvin Barbes on Sept. 24, 2023

Reviewed by: Kyle Kolaja on Sept. 19, 2023

Reviewed by: Neil Tournoux on July 12, 2023

Bought 2 scarlet hermits that are just a tad small for me. At first they both hid. Then they came out and joined each other. Then they went in 2 different directions and the last few days I've only seen one of them. Hope the other is O.K. I think next time I'll go for a bit larger crab. They're getting along with their tankmates and have added not only to the "cleanup crew" tasks, but are a pretty and active addition to a normally slow and quiet seahorse tank.

Reviewed by: Melodi Leatham on Aug. 13, 2017

Great addition to cleaner crew, and are cooler water species as well

Reviewed by: Stacy on Jan. 29, 2017

Although these guys have shown no interest in my Cyanobacteria (for which I bought them), they are extremely active as advertised. My main problem is that they like to flip my snails upside down, which causes me to be continually righting the snails that can't right themselves.

Reviewed by: Michael Dieckmann on April 6, 2015

Reviewed by: Aaron on Oct. 27, 2014

Reviewed by: Andrew Palagyi on Sept. 30, 2014

Hard workers.good quality.

Reviewed by: Joseph H Shotwell on Sept. 6, 2014

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