Anyone know what this is????

[Scaggs1117]

I’ve been noticing a few of these throughout the tank recently, reefer 525XL
They’re like fuzzy plushy little slug looking things that are white

 

[rayadog]

Pineapple sponges, don’t believe their harmful at all as is

 

[Michael Hughes]

Looks like a Stomatella snail to me, given the small mouth at the bottom.

 

[Scaggs1117]

Pineapple sponges, don’t believe their harmful at all as is

Pineapple sponges, don’t believe their harmful at all as is

Interesting, thank you

 

[Fish Fan]

If it's sessile (doesn't move) then I think this is a pineapple sponge, especially because it appears to be growing in your overflow, and they like to grow in shaded places. They are indeed totally harmless, possibly beneficial filter feeders, and very common in newer tanks. Their population will self-regulate on their own.

Here's a stock pic of pineapple sponges:

This one is upside down, but you can see it's frilly top (upside down, of course) that to me resembles the green leaves at the top of a pineapple. I'm pretty sure I see these white frills in the picture you posted:

I hope this helps!

 

[EnterName]

I second Sycon sp. or related genus (Pineapple sponge)
See page 5, post #83
Beneficial filter feeders.

 

[StartingATank]

Looks like a Stomatella snail to me, given the small mouth at the bottom.

I can see a stomatella but with stomatella snails their mouthpiece is seperate so what from their body, so I don’t think it’s that. I haven’t seen a chiton myself but could it be one?

 

[JGT]

It’s def a pineapple sponge.

 

[rayadog]

Pineapple sponges, don’t believe their harmful at all as is

They’re * GAH