How to Breed Lettuce Sea Slugs

Lettuce sea slugs, genus Elysia, can breed in home aquariums if they have the right conditions. As they are hermaphrodites, though not self-fertilizing, you need a minimum of two but there is no need to determine gender. You do need to ensure they are indeed the same species since there are at least three different species regularly sold in the aquarium trade.

Things You'll Need

  • Established marine aquarium with low flow pump and strong light
  • Nitrate test kits
  • Algae cultures
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Instructions

    • 1

      Establish a large marine tank with the minimum fauna to have a healthy tank. Don't include carnivorous fish or invertebrates that feed primarily on plankton.

    • 2

      Introduce two or more lettuce sea slugs of the same species. Preferably, purchase captive bred individuals from a reliable supplier and ask what species of algae the breeder fed the larvae.

    • 3

      Keep the light on for at least 12 hours a day. It is necessary both for the algae the sea slugs eat and for the sea slugs themselves. Lettuce sea slugs incorporate some chloroplasts from the algae into their own bodies and derive energy from them if there is enough light.

    • 4

      Maintain nitrate levels as close to zero as possible through partial water changes.

    • 5

      Provide extra algae for the sea slugs if necessary, although a large well-lit tank with live rock will probably provide them with sufficient food.

    • 6

      Remove or switch off any large pumps or protein skimmers. Powerful pumps would have the unfortunate effect of filtering out the sea slug larvae if your breeding attempts are successful. They may also damage the adults. Cover the output of the low flow pump.

    • 7

      Observe your sea slugs' behavior and watch for eggs being laid. They lay ribbon-like strips of eggs, which hatch into nearly microscopic larvae. How long the larvae remain in this stage depends on the species. The larvae of some species, such as Elysia crispata, metamorphose into tiny sea slugs, which eat the same algae diet as the adults, within a few days. Others need supplemental food.

    • 8

      Feed the larvae on phytoplankton if necessary. They are sometimes very picky about the species of algae they will eat. You can discover what is a suitable species of algae for your species of lettuce sea slug larvae from the breeder or from a marine biology or aquarium website.