The Sea Hare, latin name Aplysia Dactylomela, represents an interesting and diverse sea slug that is a soft bodied opisthobranch, with a soft internal shell made out of a pertinacious material, and large wings or “parapodia” which enable sit to swim. The Sea Hare can be found in shallow regions or at depths of over 100′. They are most commonly found in intertidal rocky shores, tide pools and lagoon biotopes. Some species of Hares, such as the California Sea Hare, can obtain a length of 15″ or so and weigh a few pounds. These mollusks represent one of the largest forms of sea slug(opisthobranches) and mollusks for that matter. The Sea Hare is different from the nudibranches in that the hare has internal gills, whereas nudibranches have what is known as “naked gills” and reside on the outside of its body. Their long tentacles were once thought to look like the long ears evident in wild hares that reside on land.
These Opisthobranches are great at removing and controlling most forms of algae as they are herbivores, feeding on vegetable matter with their radula, for the most part. Constantly foraging across the substrate in search of food, they will also help to aerate and stir up the benthic areas of a tank somewhat, similar to that of a Sea Cucumber.
Masters of camouflage, the sea hare will blend in, like an octopus, to its ambient surroundings almost becoming invisible to humans and would be predators alike. Their cryptic coloration and often drab coloration normally deters the average aquarist from pursuing one of these master of disguises. However, again with their ability to be considered a reliable and beneficial “clean up crew” addition, it would make sense to employ one of these into your diverse population of marine life.
Like the octopus, care must be taken not to handle or disturb these slugs. They are armed with an anti-predatory deterrent that helps them to ward off attack from would be predators. Ink, similar in function and chemical make-up to that possessed by the octopus, can be released by the slug to enable the slug to get away or at least ward off the potential predator as this ink is toxic to fish and it also alters the smelling response of fish. These aids help the slug to survive the perils of being a slow moving, internal soft shelled, large herbivore. This, normally a purple color, ink can wreck havoc on water parameters as if released, will downgrade water quality requiring a quick response to remove this ink as fast as possible. A water change, efficient skimming and the use of carbon should help to remove this ink fairly rapidly to reduce the negative effects caused by this ink being released in a closed system environment.
Unfortunately, the sea hare doesn’t last more than a year. These hermaphrodites are a short lived specimen that reproduce via long chains of sea slugs. They release their eggs every summer and the eggs are similar in appearance to long yellow strands of spaghetti.
There is a specific Aplysia facility geared towards reproduction and rearing of the sea slug. This facility, known as, NIH, The University of Miami National Resource has been in operation for some time now, in hopes of advancing the biomedical research throughout the world. Originally located in Woods Hole, Massachusetts, the facility moved to Miami, as a way of producing the sea Hares dominant food supply, Garcilaria algae year round. They have also developed a state of the art grow out lab facility to grow roughly 12 tons of this red seaweed/algae for the sea hares to consume.
These mollusks, though short lives, should be considered as another nice addition to your clean up crew in efforts to keep the benthic areas of you tank algae free and substrate aerated in addition to the usual hermits crabs, snails and sleeper gobies.