Resolved I have no clue what this is.

Something with an internal shell would typically be a scutus (also called elephant slug because it looks like a slug and often have an elephant-looking trunk). Those are reef safe. Cowries are sometimes reef safe and sometimes not. Abalones also have internal-looking shells. Again, some are reef safe and some are not.

If you irritate it enough, it will pull it's skin flaps into it's shell and then you can see what the shell looks like. It will be easier to ID that way.

 

sorry this it the best pic i can get.

 

Man, I skip a few hours checking in here and you guys are ready to condemn an innocent opisthobranch to death! It's a strictly-vegetarian haminoeoid species, and a neat hitchhiker (or acquisition, if you caught him in Florida). The pics confuse me, because it looks like one species in some of the pics, and a different species in the others. The curled up pic looks very much like a dark variation of Smaragdinella calyculata:

The Sea Slug Forum - Smaragdinella calyculata

Problem is, I've seen lots of S. calyculata, and I've never seen them stretched out crawling like the other pics show.

I think it's a Haminoea species, and probably one of the Florida/Caribbean species. The most common and consequently most likely is probably Haminoea antillarum, which has tiny orange dots under the surface of the animal. I ran the exposure way up high on one of your early pics, and it looks like I can see the orange dots. Yours is very dark for that species, though. Can you see the orange dots like this?

The Sea Slug Forum - Haminoea antillarum

Another Caribbean possibility is Haminoea elegans. It's rarer, but is always darker, and looks pretty close to yours:

The Sea Slug Forum - Haminoea elegans

There are a few other species in the superfamily Haminoeoidea, but most of them are very different or live in cold water. Maybe you can look at yours under magnification and see if you can tell which it is? None of them eat anything other than algae, so they should all be reef safe.

Cheers,



Don

 

Thanks Don (as usual)

 

My pleasure. I've killed so many snails, it's nice to maybe save one or two occasionally, LOL. Most of the opisthobranchs have fairly short life cycles, though, so I might not have extended his life by much.

Cheers again,


Don

 

I can't speak for the OP, but from his very last pic taken with the organism on his hand, and your first guess, Don--it looks a lot like the Smaragdinella calyculata you pictured.

 

If they are actually flatworms.... especially the brown ones then I would suggest to use
Flatworm eXit by Salifert.. that usually takes care of the problem. Usually I would leave them alone but the brown ones ... as far as I know... can do some damage.
Anybody else with any suggestions...

 

I still have it. I put it in a plastic cup with holes, and I’m floating the cup.

 

So should I put it back in the tank?

 

Sure, it's an algae eater and won't hurt anything, whether it's a Haminoea or the closely-related Smaragdinella. You might try getting some good macro photos of it, one way or another, before you put it back. It's an interesting animal.

Cheers,



Don