Green Sea Urchin
Lytechinus variegatus
An excellent algae-grazing sea urchin from the Western Atlantic, uniquely known for adorning its spines with shells and debris for natural camouflage.
Température de l’eau
22 - 27 °C
Valeur du pH
8.1 - 8.4
Type d'eau
Marin
Type d'invertébré
Sea urchin
Taille adulte
11 cm
Groupe minimal
>= 1
KH
8 - 12 dKH
Rôle écologique
Herbivore
Sensibilité au cuivre
High
Description de l'espèce
Geographical Origin and Habitat: Lytechinus variegatus (Green Sea Urchin) is native to the Western Atlantic Ocean. Its geographical range extends from the coasts of North Carolina (USA) and Bermuda, down through the Gulf of Mexico and the Caribbean Sea, to southern Brazil. It predominantly inhabits seagrass meadows (mostly *Thalassia testudinum*), sandy lagoons, and shallow coral reefs at depths from 0 to 50 meters.
Taxonomy: This species belongs to the family Toxopneustidae. It features a spherical calcareous test covered with numerous short spines. It is commonly referred to as the variegated sea urchin due to the high color variability exhibited by different geographical populations.
Social Behavior: It is a peaceful, active benthic organism. It is highly famous for its 'covering behavior,' using its tube feet to grasp and carry shells, pebbles, macroalgae, and other debris over its body. This acts as camouflage against predators and provides protection against solar UV radiation.
Coloration and Sexual Dimorphism: The coloration of the test and spines varies widely, including shades of light green, white, pink, or deep purple. The spines often feature tips with contrasting colors. There is no external sexual dimorphism; males and females look identical, and sex can only be determined during spawning.
Soins, reproduction et cohabitation
Tank Setup: Requires a marine aquarium of at least 100 liters (30 gallons) with stable live rock structures for climbing and grazing. Provide loose shells and small rubble on the sand bed to support its natural covering behavior. Ensure rockwork is secure, as the urchin can bulldoze loose decorations.
Diet and Feeding: An outstanding herbivore and detritivore. It feeds primarily on microalgae, filamentous algae, diatoms, and macroalgae. If the aquarium lacks sufficient natural algae growth, supplement its diet with dried seaweed (nori) attached to a clip or weighted rock, as well as herbivore sinking pellets.
Water Quality: Keep standard marine parameters stable: temperature 22-27 °C, pH 8.1-8.4, and specific gravity 1.023-1.025. Adequate levels of calcium (400-450 ppm) and magnesium are essential for shell development. It is highly sensitive to copper treatments, rapid salinity shifts, and high nitrates.
Compatibility and Tankmates: 100% reef safe and peaceful. It will not harm corals or sessile invertebrates. Avoid housing it with specialized urchin predators, such as triggerfish, puffers, and large wrasses, which can easily flip the urchin over and consume it.
Aquarium Breeding: Breeding in home aquariums is extremely difficult. It is a broadcast spawner, releasing eggs and sperm simultaneously into the water column. The planktonic larvae require specific phytoplankton diets and specialized tanks, and are usually cleared by standard filtration.
Risks and Diseases: Spiny loss is the primary indicator of severe stress, starvation, or poor water quality (osmotic shock). If the urchin begins losing its spines, check water parameters immediately. Never expose the urchin to air during acclimation and transferring, as trapped air can be fatal.
Origine et répartition géographiques
Lytechinus variegatus (Green Sea Urchin) is native to the Western Atlantic Ocean. Its geographical range extends from the coasts of North Carolina (USA) and Bermuda, down through the Gulf of Mexico and the Caribbean Sea, to southern Brazil. It predominantly inhabits seagrass meadows (mostly *Thalassia testudinum*), sandy lagoons, and shallow coral reefs at depths from 0 to 50 meters.
Origine
Océans tropicaux et récifsAmérique du Sud hors AmazonieAmérique centrale et CaraïbesAmérique du Nord
Profil d'invertébré
- Régime alimentaire
- Omnivore
- The diet of Lytechinus variegatus typically consists of organic detritus, microalgae, or specific planktonic particles. In a home aquarium, they constantly forage along the substrate or rockwork looking for nourishment. Supplemental feeding with specialized invertebrate pellets or liquid foods may be necessary. Ensuring a varied and nutritious diet will promote vibrant colors and long-term health. Overfeeding should be avoided to maintain optimal water quality.
- Rôle écologique
- Herbivore
- In the wild, Lytechinus variegatus plays a crucial role in maintaining the balance of its native ecosystem. They often act as natural cleaners, breaking down waste materials and unconsumed food. Their constant movement helps aerate the sand bed and prevent the buildup of toxic gases. By managing algae growth, they create space for slow-growing corals and sponges to thrive. A balanced aquarium ecosystem relies heavily on their diligent cleaning efforts.
- Taille adulte
- 11 cm
- Risque de saut
- No
- Sensibilité aux chocs
- High
- This invertebrate is highly sensitive to rapid fluctuations in water parameters. Sudden changes in temperature, salinity, or pH can cause severe osmotic shock and death. A slow and careful acclimation process, preferably drip acclimation, is absolutely necessary. Maintain stable aquarium conditions through regular monitoring and automated top-offs. Avoid performing excessively large water changes at once.
- Calcium et minéraux
- High
- Proper calcium levels are absolutely vital for the structural integrity and growth of this species. They continuously extract calcium carbonate from the water to build their shells, skeletons, or protective tubes. Maintaining calcium levels between 400 and 450 ppm ensures they remain healthy. It is also important to balance alkalinity and magnesium alongside calcium supplementation. Regular testing is required in heavily stocked reef aquariums.
- Mue
- Yes
- If applicable to its morphology, this invertebrate undergoes periodic molting to facilitate growth. During the molting process, the organism becomes extremely vulnerable to predation and stress. It is crucial to provide ample hiding spaces, such as caves or crevices, where they can retreat safely. Do not remove the discarded exoskeleton, as they often consume it to quickly replenish essential minerals. Disturbing them during this delicate phase can lead to fatal complications.
- Reproduction
- Oviparous
- Reproduction in the home aquarium is often challenging and rare for many invertebrate species. Most require highly specific environmental triggers, such as temperature shifts or lunar cycles. The resulting larvae usually have a prolonged planktonic stage, making them difficult to rear. Specialized food sources like phytoplankton are needed to sustain the offspring. Consequently, most specimens available in the hobby are wild-caught or professionally aquacultured.
- Compatibilité et compagnons
- Reef safe
- Compatibility varies largely based on the specific species and tank mates. They are generally peaceful but can fall prey to aggressive or predatory fish. Ensure they are housed with calm tank mates that will not nip or harass them. Research individual species requirements to avoid territorial disputes. Always monitor new additions carefully to ensure harmonious interactions.
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