Nudibrach or snail + aiptasia?

[Lsusaints7]

Is this a nudibrach or a baby snail? Is the second one aiptasia?

 

[a.t.t.r]

Flatworm on the first and feather duster on the second.

 

[WheatToast]

Flatworm on the first and feather duster on the second.

Second!

 

[Isopod80]

Amphiscolops sp. flatworm. They are predators of copepods and other tiny organisms. They won't hurt corals or other tank inhabitants but they can reproduce quickly in some tanks. You're best bet is to suck up the ones you see with a turkey baster. Aside from that no other management should be necessary. And yes, the other is a harmless feather duster worm.