ID please on large flatworm

[steveu]

Hi all,

Can anyone please ID this monster flatworm-type thingy that I just found in a 20 gall. Its about 3 inches long ! Its ages since I added any liverock or corals - scary how it must have hidden for so long in a little tank !!!

Thanks, Steve

 

[greenbean36191]

Well, it's a large flatworm- a polyclad to be more precise. It's a predator of mollusks.