Livestock | Marine | Marine Inverts and Snails | Slugs

Keeping Sea Slugs and Sea Hares in Marine Aquariums

Sea slugs and sea hares are intriguing, often vibrantly colored invertebrates that bring unique beauty and utility to marine aquariums. Ranging from algae-grazing sea hares to pest-eating nudibranchs, these soft-bodied mollusks are excellent for specific aquarium roles—though they often require careful placement and experienced care.

General Care Tips:
Sea slugs and sea hares thrive in stable, mature aquariums with plenty of natural food sources, peaceful tankmates, and minimal physical hazards (like strong intakes or uncovered powerheads). Ideal conditions include a temperature of 72–81°F and a pH between 8.1–8.4. These invertebrates are highly sensitive to water quality, so consistent parameters and low nitrate levels are essential.

Feeding:

• Sea Hares (e.g., Dolabella auricularia, Aplysia spp.): Primarily algae grazers, these peaceful herbivores can help control nuisance algae such as hair algae. In low-algae tanks, supplement their diet with dried seaweed (nori) or algae wafers.

• Nudibranchs (true sea slugs): Many are highly specialized feeders, with diets that include specific sponges, hydroids, or pests like Aiptasia anemones or flatworms. Species like Aeolidiella stephanieae are valued for pest control but will starve without their preferred prey.

Compatibility and Behavior:
Sea hares and many sea slugs are peaceful and reef safe, but require protection from aggressive fish, strong currents, or powerheads where they can be injured. Sea hares are excellent grazers but should be monitored in smaller tanks, as stressed individuals can release ink. Nudibranchs vary—some are reef safe and beneficial, others may feed on corals or have very short lifespans due to dietary limits.

Popular Species:

• Dolabella Sea Hare (Dolabella auricularia): Algae-eating, peaceful, and relatively hardy—great for reef-safe algae control.

• Lettuce Sea Slug (Elysia crispata): Photosynthetic and feeds on algae; colorful and peaceful.

• Aiptasia-Eating Nudibranch (Aeolidiella stephanieae): Effective natural predator of Aiptasia anemones; needs a steady food source.

• Chelidonura varians: Known for consuming flatworms—valuable for pest management.

• Coriocella hibyae (Quasimodo Slug): Unique and slow-moving; filter feeder that adds visual interest.

• Other Nudibranchs: Many are beautiful but often unsuitable for aquariums due to their specific and difficult-to-provide diets.

Special Considerations:
Most sea slugs and sea hares have soft, vulnerable bodies and can be injured easily. Handle with extreme care and always acclimate slowly using the drip method. Sea hares, in particular, may release a purple ink when stressed—this is generally harmless in a well-filtered tank but should be watched carefully. Many species have relatively short lifespans (often 6–12 months), so understand each one’s needs before purchase.

Summary:
Sea slugs and sea hares offer incredible visual appeal and practical benefits like algae or pest control in reef aquariums. While some are beginner-friendly, others require species-specific diets or advanced care. With the right conditions and thoughtful selection, these invertebrates can be rewarding and beneficial additions to the marine aquarium.