Common name: Hairy Urchin Shrimp

General Information

The Hairy Urchin Shrimp (Sandimenes hirsutus) is a captivating and tiny crustacean native to the Indo-Pacific region. It earns its common name due to its association with sea urchins, often living among their spines for protection. Despite its small size, Sandimenes hirsutus plays an important role in maintaining reef biodiversity, contributing to the overall health of its ecosystem.

A relatively recent addition to the aquarium trade, the Hairy Urchin Shrimp has gained popularity due to its unique appearance, intriguing behaviors, and relatively straightforward care requirements. It is particularly favored by nano tank enthusiasts who appreciate its quirky charm.

Care

Caring for Sandimenes hirsutus requires some attention to detail, primarily due to their small size and delicate nature. These shrimp thrive in specialized nano tanks that offer a stable, mature environment. They do best in aquariums with ample live rock and microalgae, which provide both food and hiding spots. Maintaining stable water conditions with minimal fluctuations is crucial for their well-being.

A tank size of at least 20 liters (approximately 5 gallons) is recommended for a small group of Hairy Urchin Shrimp. Gentle filtration is essential to prevent stressing these fragile creatures. A habitat rich in microalgae and biofilm helps replicate their natural surroundings, supporting both their dietary needs and their instinctive behavior to seek shelter.

Diet and Feeding

Sandimenes hirsutus are detritivores, feeding mainly on biofilm, microalgae, and detritus found in their environment. In captivity, they can be supplemented with high-quality powdered foods formulated for filter feeders, along with occasional offerings of micro-plankton or infusoria.

Feeding should be done sparingly, as these shrimp are quite efficient at finding food within the tank. Overfeeding can lead to water quality issues, so it's important to monitor their intake and adjust feeding as necessary to maintain a clean, healthy environment.

Behavior and Compatibility

The Hairy Urchin Shrimp is peaceful and non-aggressive, making it an excellent candidate for community nano tanks. They exhibit endearing behaviors, such as hovering and "dancing" among the substrate and plants while foraging for food. Due to their small size, they should only be housed with other small, non-aggressive tank mates. Larger species may inadvertently harm or outcompete them for food. Ideal companions include small snails and other tiny invertebrates that are equally gentle.

Symbiosis

Sandimenes hirsutus has a fascinating mutualistic relationship with sea urchins. By living among the spines of sea urchins, the shrimp gains protection from predators, while the sea urchin benefits from the shrimp's cleaning activities. The shrimp helps remove detritus and organic particles that settle on the urchin's surface, contributing to a cleaner, healthier environment for both species. This symbiosis is a key aspect of the shrimp's natural behavior and helps both organisms thrive in their shared habitat.

Health and Common Issues

Hairy Urchin Shrimp are generally hardy when provided with stable conditions and proper care. In captivity, they can live for approximately 1-2 years. Ensuring good water quality and a consistent food source is essential for their health. When selecting Hairy Urchin Shrimp, choose active individuals with intact, fuzzy appendages. Avoid shrimp that appear lethargic or have damaged limbs, as these may be signs of stress or poor health.

Common health issues include sensitivity to fluctuations in water quality and the risk of predation by larger tank mates. Regular monitoring of water parameters and diligent maintenance of the aquarium environment are key to preventing these problems and keeping the shrimp healthy.

Habitat

In the wild, Sandimenes hirsutus is typically found in shallow coastal waters and reef flats, often among seagrasses and algae beds, where they can blend in with their surroundings. Their distribution spans the warm waters of the Indo-Pacific, particularly in regions with abundant marine vegetation.

These shrimp thrive in environments rich in microalgae and detritus, which serve as both food and camouflage. To ensure their success in captivity, it is crucial to replicate these natural conditions as closely as possible. A well-designed tank setup that includes plenty of live rock, microalgae, and stable water conditions will help them thrive and exhibit natural behaviors.