Sea Hares

Many reef aquarists who have some experience in maintaining their aquariums that is maintaining seawater quality at a high level are constantly on the lookout for something that could fall into the category of ‘unusual’.

The life form that is found – if found – has to meet certain criteria in the aquarist’s mind before it receives the sea of approval. First and foremost, it has to be reef safe, in other words it must not start eating the aquarist’s coral collection! Second, it has to contribute something to the reef, this contribution could be beauty, or shape, or a combination. Or it could be just weird.

A life form that is not only interesting, could probably be called beautiful, and in addition is useful to the aquarist is the sea hare. These are often termed ‘slugs’ but this is a little unfair, as the word ‘slug’ could initiate thoughts of the gardening problem slug which eats if it has the chance much of the garden plants. Sea hares don’t deserve this kind of press. They will actively consume algae in the aquarium. The aquarist with a green hair algae problem would no doubt be delighted, but it is possible the creatures would also find decorative algae a pleasant food.

Sea hares are sometimes obtainable from the local fish shop, or if not can usually be found for sale wider afield. They are also being commercially bred too, which is a great boon. Its wonderful how many sea creatures, on a lengthening list, are now being bred.

The aquarist if intending to buy one of these creatures has to show some caution, but no more than when buying a fish. It is important to know the species that is being obtained; this information should be readily obtainable from the seller. If it isn’t, then don’t buy.

Why should caution be necessary? When buying a fish it is necessary to know the species so that the eventual size is known. Many fish are small when at the dealers but grow quite rapidly if nature intended them to do so.

Similarly, sea hares have different sizes. For example, one type which is of no interest to the aquarist is reported to grow to 39.5 inches (circa 100 cm), just a bit large for our aquariums! Another, the spotted sea hare (Aplysia californica) could grow to about 15 inches (circa 38 cm). Another much smaller species commonly called the green sea hare (Phyllaplysia taylori) could grow to between ¾ inch (circa 2 cm) and 3 inches (circa 7.5 cm). The spotted sea hare will usually eat good quantities of algae, the preference being for green. The corals that that the sea hare is living with need to be fairly robust and well anchored, particularly as the hare’s size increases. The smaller hare is not such an easy feeder, as it lives in sea grass ‘fields’, the sea grass is its reported food. They are reported to eat algae but this could prove to be inadequate. Also, predators in the aquarium could take an unhealthy interest in the creature.

Sea hares do not have any particular demands apart from the usual one of good seawater quality. If the aquarist is cautious in purchase and is able to provide the food required, then the aquarium will be enriched with a creature that some would call beautiful, others different, and others weird.

There is one link provided and a video. The link is to an advanced website, but this should not put any reader off as the text is straightforward. Just scroll down until the sections that are of interest are found. The video shows a sea hare in an aquarium. Note the camouflage.