Nudibranch ID? Friend or foe?

UncommonSense

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This lil’ guy came out of live rock from KP aquatics, Gulf of Mexico!

First spotted by a local reefing buddy in his new tank this morning, 13 days after adding the live rock…

I’m pretty confident it’s a nudibranch, but that’s about as far as my ability to ID it goes…

Thoughts? Good guy or bad guy?

IMG_8255.jpeg
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The pic is a little blurry but it looks like a Blue Velvet nudi. They are planaria flatworm eaters. I think that is their only diet like the berghia with aiptasia. I think they also release toxins when they die so should be watched so it doesn’t take out the tank. Others will weigh in with their thoughts as well.
 
The pic is a little blurry but it looks like a Blue Velvet nudi. They are planaria flatworm eaters. I think that is their only diet like the berghia with aiptasia. I think they also release toxins when they die so should be watched so it doesn’t take out the tank. Others will weigh in with their thoughts as well.
I’m still not sure why the pics are blurry… probably the amount of zoom required to show detail…

It’s definitely not a Blue Velvet; it’s black and white, with no split “tail” and a sizable fan of gills on it’s back!

The potentially specialized diet is my biggest concern, aside from it potentially being a terrible pest species I’ve yet to learn about!
 
I always thought nudibranches were friends generally, but the issue comes down to diet and getting sucked into the powerhead.
 
If it has any "glow" to it, it most likely will eat coral.
 
The pic is a little blurry but it looks like a Blue Velvet nudi. They are planaria flatworm eaters. I think that is their only diet like the berghia with aiptasia. I think they also release toxins when they die so should be watched so it doesn’t take out the tank. Others will weigh in with their thoughts as well.
I’m still not sure why the pics are blurry… probably the amount of zoom required to show detail…

It’s definitely not a Blue Velvet; it’s black and white, with no split “tail” and a sizable fan of gills on it’s back!

The potentially specialized diet is my biggest concern, aside from it potentially being a terrible pest species I’ve yet to learn about!
Thanks for the correction. I definitely couldn’t tell. I am following to see what it ends up being and hopefully good and not a very specialized diet!
 
I know you said black and white but does it look anything like this guy?

20250903_074939_94C45FED-7733-42D9-B594-AD8C71A668E1.png

Supposedly these are in Florida. I’m totally hooked on finding out now about that little gut!
 
I know you said black and white but does it look anything like this guy?

20250903_074939_94C45FED-7733-42D9-B594-AD8C71A668E1.png

Supposedly these are in Florida. I’m totally hooked on finding out now about that little gut!
That’s an awesome looking nudibranch!

It does have a similar body shape, but different color patter! Same genus maybe?
 
If you knew me you’d know I’m a researching kind of gal. I wonder if it somehow drifted up from somewhere else? I’ve looked high and low in slugs and nudis in Florida and don’t see anything with the color or pattern you have!! Still 🧐!
 
If you knew me you’d know I’m a researching kind of gal. I wonder if it somehow drifted up from somewhere else? I’ve looked high and low in slugs and nudis in Florida and don’t see anything with the color or pattern you have!! Still 🧐!
I appreciate the diligent research!

I went so far as doing a Google reverse image search to see if I could spot another one…

No luck… I looked at hundreds of photos of different species… here’s the closest visual match I can find, with zero information about it!

IMG_8281.png


It also appears to still be a different species, or possibly the same species with a less speckled white pattern!
 
If you knew me you’d know I’m a researching kind of gal. I wonder if it somehow drifted up from somewhere else? I’ve looked high and low in slugs and nudis in Florida and don’t see anything with the color or pattern you have!! Still 🧐!
I appreciate the diligent research!

I went so far as doing a Google reverse image search to see if I could spot another one…

No luck… I looked at hundreds of photos of different species… here’s the closest visual match I can find, with zero information about it!

IMG_8281.png


It also appears to still be a different species, or possibly the same species with a less speckled white pattern!
Oh, what about this guy?

http://www.seaslugforum.net/find/11807
 
Hypselodoris acriba.
I think we’re moving in the right direction, there are some interesting differences though!

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http://www.seaslugforum.net/find/13672
It does appear, however, that any of the likely genuses are sponge eaters… so, it’s going to have to be pulled out…

IMG_8258.jpeg


— would anyone with the appropriate system be interested in housing this odd specimen?
 
Hypselodoris acriba.
I think we’re moving in the right direction, there are some interesting differences though!

IMG_8291.jpeg
IMG_8292.jpeg


http://www.seaslugforum.net/find/13672
It does appear, however, that any of the likely genuses are sponge eaters… so, it’s going to have to be pulled out…

IMG_8258.jpeg


— would anyone with the appropriate system be interested in housing this odd specimen?
I would love to, how ever I am in Seattle Washington so I might be a ways away from where you are located
 

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