Scutus reproduction

October 20, 2005
From: Rob Wedin

Thanks for maintaining this little Scutus spot on the internet!
I now have two of these in my 120g reeftank. I'd love to help foster a reproduction event [see message #11385 ], but am unsure about the following:
Both Scutus are almost definitely direct siblings, from the same tank but acquired years apart. Does this hinder their mating chances?
Hermaphrodites - out of two, will one of them change to the the opposite sex, or would I have to aquire opposite-sex limpets?
Thanks again!
Rob Wedin (ribs)

Wedin, R., 2005 (Oct 20) Scutus reproduction. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Rob,
I am not sure why I encourage Scutus questions. I really have far too many sea slug questions to spend time on a little snail. However it certainly illustrates one way the Forum increases our knowledge. While I have helped a lot of aquarium people discover what this animal is, they in return have given us a lot of new information about its reproductive behaviour. While theoretically we 'knew' that it should relase its eggs and sperm into the water,  I don't think it has actually been observed previously.

So to your question. I am not sure why you think your two animals are siblings. It's possible they are, but also they could have arrived on separate occasions on live rock. But to answer your question, sibling mating is not uncommon in nature. However, Scutus is not an hermaphrodite, so unless you have a male and a female, I'm afraid mating events are out of the question. And before you ask.... there is no easy way of identifying their sex - unless you dissect them - which means killing them, which would rather defeat the purpose of the exercise.
Best wishes,
Bill Rudman

Rudman, W.B., 2005 (Oct 20). Comment on Scutus reproduction by Rob Wedin. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

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