Looks like a snail without shell

[AlessioSG]

Hi Guys,

I just found this creature moving very slowly on my aquarium glass. Can you help me to ID it, please? Thanks.

 

[Formulator]

Looks like a nudibranch. Probably berghia nudibranch. They only eat aiptasia so if you don’t have any, it will likely starve. They are incredibly valuable to folks with aiptasia infestations though. If you find more, might be able to sell them for a pretty penny. Large ones can be as much as $20-30 each.

 

[AlessioSG]

Berghia nudibranch is usually whiter and smaller. Considering the amount of aiptasia I kill every week, I would be glad of having one.
Any other nudibranch is fine. Just want to make sure it is not a flatworm.

 

[Formulator]

The intricate lace-like protrusions on its back kind of scream nudi to me.

 

[AlessioSG]

I tend to agree with you. However, I check on a long list of types of nudibranches and no one looks like that. Also, it seems that there are no little horns/antennae. Never encountered this type of creature before.

 

[DMG Reef]

It’s a Tritoniopsis elegans nudibranch. It feeds on soft corals and sometimes comes in on leather corals. I would remove it.