What Could it Possibly Be and How Did it Get Here

redfishbluefish · Dec 12, 2018

This one has me scratching my head. I haven't added anything to my tank in over two years or so...can't remember the last thing I added. Walked into the fish room and see this on my front glass:

Now I can't see the top side of this creature, but I do make out a "horn" on the right upper side of this beast, and I'm thinking it's a rhinophore of a nudibranch. So I scrape her off with a razor blade scraper and catch it in a net and transfer it to a netted holding cage. It folded up on itself, but here's a very poor picture of her.

So at this point I'm still thinking nudi, and you're seeing cerata on its back.

The following day it has opened up and found it's way into the corner...again, sorry, bad picture. First, here's a regular shot without zooming in, to give you an idea of size....in the upright corner:

And now a close up:

So now I'm thinking it's not a nudi because I don't see rhinophores or oral tentacles. The only thing I'm seeing is this group of tentacles in the center of this creature. Could it be a majano? And the bigger question, not adding anything in years, how did it get here?

If it moves down into the light, I'll try getting a better picture.

rkpetersen · Dec 12, 2018

Wow, that's crazy. Probably been there awhile, hiding out. I'd still guess that it's some type of nudi or other sea slug that doesn't have external gills and has small variable tentacles, mainly on the basis of that first picture when it was still happy.

Crabs McJones · Dec 12, 2018

It almost looks like a Warty Sea Anemone

KJ · Dec 12, 2018

Look like anemone @reef lover

redfishbluefish · Dec 12, 2018

What's interesting is that the second picture clearly shows the "tentacles" are ringed. Have you ever seen cerata with rings? Or an anemone with rings?