Critter # 2 ID what the heck is this

[DJC]

Hey all
So was watching my tank today then all of a sudden this creature appeared out from behind a rock and scared the crap out of me because it’s so big

Not sure where he has come from I’ve literally not added anything to my tank in over a month and half and the last lot of anything I added was Australian barrier reef fish

I’ve attached some photos this creature has mimicked the same colour as my live rock and has a shell type back and body seems to be a slug type

Harmful critter or good critter ?

 

[Tonycass12]

Stomatella snail

 

[WheatToast]

Stomatella snail. These are beneficial algae grazers that reproduce in captivity.

 

[DJC]

Amazing this one looks a little different to the last stomatella snail I ID,d this just means I now have multiple in my tank


Do I need to be cautious on them reproducing ?

 

[WheatToast]

Do I need to be cautious on them reproducing ?

No. Their population is kept in check by the amount of algae available to them.

 

[Cell]

Stomatella snails are awesome.

 

[WalkerLovesTheOcean]

I love stomatella snails! Keep them, I found one from my live rock last light, before I did a high salinity water dip, I knocked him off, and he fell upside down, and I watched him flip himself over! So cool!