Growing Like…..Weeds!

Things have been going quite well in the in-line refugium known as Box of Slugs 2.0.  Although it might not be considered a plus in most aquaria, algae have been very successful in the new tank.  A less sophisticated aquarist might dare to call the tank an eyesore, yet the slugs could not be happier.  Here are a few of the youngsters grazing on what I think is Derbesia.

Trio of Youngsters, Box of Slugs 2.0

Trio of Youngsters, Box of Slugs 2.0

Indeed, it has been a great time for the little guys, and they have been growing like the little slug-weed chimeras that they are.  Many have gone beyond the twiggy little worm stage to looking and behaving like proper small slugs.

At this size, I am still unsure that they are all E. clarki.  The one below is most likely E. tuca almost looks like E. chlorotica, or maybe E. subornata, and does not have much in the way of parapodia.

Elysia not clarki?

tuca chlorotica not clarki?

The small slugs below look more convincingly like the adults in the tank.  Rolled rhinophores, parapodia starting to ruffle, chloroplasts throughout the body, including the foot, all point to the little guys being the common lettuce slug of the Keys.

Young E. clarki, 2/8/15

Young E. papillosa clarki, 2/8/15

Baby slug exploring

Baby slug exploring

Will they get spots and ruffles like the purported parents?  Time will tell. [note added later: these are not young E. clarki, as a few of the edits above indicate]

Adult E. clarki 2/5/15

Adult E. clarki 2/5/15

They still have a long way to go to get to full size, as can be seen in this photo of the adult from the photo above grazing on Bryopsis while a youngster wanders about.

Growing baby and parent 2/13/15

Growing baby and parent 2/13/15

One of the more interesting developments is the appearance of very small, dense egg masses in Box of Slugs 2.  At first, I attributed them to the small herd of E. crispata that arrived a few weeks ago, since I have no idea of the size or appearance of their egg masses.  I need to start putting a ruler or something in the photo for scale, but this clutch is about the size of the first coil of the a standard E. Clarki mass from Box of Slugs 1 (shown here, for example), and the little embryos are packed much more tightly.

Egg Mass 2/14/15

Egg Mass 2/13/15

As mentioned above, I thought these were eggs from crispata, but was thrown for a bit of a loop when I saw one of the youngsters curved around the mass as if laying them.  Can they really be mature enough to lay eggs?  I collected the mass below, and am documenting the embryos’ development.  They are definitely fertile, as indicated by the classic circling movements inside their eggs, and maybe this time I can get a brood to mature in a controlled environment and find out which species they turn into.  Stay tuned.



  1. Reply
    Andrea February 15, 2015

    Adorable! If you do have several species, what do you have planned? Do you plan to compare behavior? Life history? Kleptoplasty? Nervous systems? I’ve not read enough to know what has been done. Do you have questions in mind?

    • Reply
      Dave February 15, 2015

      For the moment, I am trying to identify them and maintain them. At this point, I think that at least one of the species is E. subornata, but I am very unhappy that Bill Rudman’s Sea Slug Forum was shut down when they cut off his funds. There are still a few people I can contact about IDs.

      I suspect that all of the candidate species are kleptoplastic. The photos indicate that they are jammed with chloroplasts. Assuming they are sustainable, the first goal is to stain their nervous systems to get a sense if the arrangement of nerves and ganglia differs between species. Then we can move on to electrophysiology to get a sense of how they measure and process light information.

      For the moment, they all seem to be feeding and growing on the assortment of algae available in the tank. Will need to order some more of the calcareous algae when the weather warms up.

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