Wedge Sea Hare

Wedge Sea Hare: The Giant Algae Grazer

The Wedge Sea Hare (Dolabella auricularia) is a giant marine mollusk belonging to the sea hare family (Aplysiidae). It is one of the most effective and dedicated herbivores available for the marine aquarium, sought after specifically for its voracious appetite for nuisance hair and film algae.

Native to the Indo-Pacific, this invertebrate gets its common name from its distinctive, broad, and somewhat flattened, wedge-shaped posterior. Its body is mottled green, brown, and tan, providing excellent camouflage in the rockwork and substrate. While most specimens sold in the hobby are 4 to 8 inches, this slug can reach an impressive length of up to 12 inches (30 cm) in a large, mature system, with maximum wild sizes reported up to 16-20 inches.

Due to its potential size and high grazing demand, the Wedge Sea Hare is best suited for large, mature aquariums (75+ gallons) with persistent algae problems. It is a peaceful animal, but it is classified as Intermediate to Expert Only due to its sensitivity to transport, water quality swings (especially high nitrates), and the critical need for a continuous, abundant food supply.

Diet & Compatibility:

• Diet: The Wedge Sea Hare is a dedicated Herbivore and a prolific generalist grazer. It feeds primarily on filamentous algae (Hair Algae), diatoms, detritus, and various types of macroalgae in the aquarium.
• Feeding: An abundant, constant food source is essential. Once a tank's nuisance algae is consumed, the owner must supplement the diet daily with high-quality prepared foods, such as sheets of dried macroalgae (Nori/Seaweed), algae wafers, or cultured Caulerpa. Starvation is a common cause of death.
• Reef Compatibility: It is Reef Safe. This animal does not eat corals or other sessile invertebrates. However, its large size means it may accidentally knock over loose coral frags or rockwork as it moves.
• Temperament: It is Peaceful. It will not harm fish or invertebrates. Ideal tankmates are small, docile fish.
• Defense Mechanism: When stressed or harassed, the Sea Hare can release a thick, reddish-purple ink into the water. This ink can be irritating or mildly toxic to some sensitive fish and invertebrates. A strong protein skimmer and chemical filtration (carbon) should be running, and a water change is recommended if a large amount is released. Do not house with aggressive fish (e.g., Triggerfish, Puffers, large predatory wrasses) that might nip at it or induce an ink release.

Quick Facts

• Scientific Name: Dolabella auricularia
• Primary Common Name: Wedge Sea Hare
• Other Common Names: Blunt-end Sea Hare, Elephant Slug, Giant Sea Hare
• Origin: Indo-Pacific (Widespread)
• Max Size: Up to 12 inches (30 cm) in the aquarium, larger in the wild
• Temperament: Peaceful (Expert Care Required)
• Diet: Herbivore (Voracious algae eater)
• Minimum Tank Size: 75+ Gallons (Requires mature tank with abundant food)
• Reef Compatibility: Yes (Excellent algae control)