flat worms

[fishcraze]

I saw Josh's thread about the Alamo fish store that's infected w/ flat worms.. How does the flat worm look like? does anyone have any pictures of them or a website that has them? I several critters in my tank/ sump but not sure what they are and if they are harmless or not.. and need help to identify them. Here are some of them:
- Yesterday, I saw some type of worms on the glass of the sump: flat body like a gellyfish, its body is pretty transparent -since you can see thru it, only one little dark spot in the middle - maybe the head/ eye??? it moves like a nudibranch does. I don't see them before.. are they flat worms - the harmful ones?
- another type of critter has a many little legs on the sides w/ a solid gray body (kind of bent). They move pretty fast, and i saw a lot of them in the caulepra.. is it bristle worm?
- another one w/ a round, oval, white (as milk) body w/ a little crown on the top. Its body is similar to that of a squirt... these critters has multiply like crazy in the tank and i see a lot of them on the rock or on the stony part of the corals.. i saw these critters for a long time ago (several months), and look like they didn't do any harm to corals/fishes, except they keep multiply fast.
Can anyone give me some idea about what are those critters?

[Tim Marvin]

Flat worms have a forked tail sorta. The rest sounds like pods and tunicates. No problem, if fact you want good colonies of these critters.

[fishcraze]

Thanks for your quick replies, guys. A person in the Marsh group said that it's a sea squirt - could be since it looks like a squirt... But then i also looks similar to the flat worm in the pics except that it's body is transparent, no red or pink section at all.. so i hope it's not the bad type.

[fishcraze]

sounds interesting. The critters i described is too small to catch a copepod.