well i just thoughti would post this because there are lots of problems with flat worms in peoples tanks.
i bought a fairy wrasse about a month ago before i went away to toronto for 3 weeks.. my sister was looking after my tank and kept it alive....
the fish is a madator wrasse/ whip-fin wrasse

as you can see in the pic there are flat worms..
i was looking in the tank today and noticed it was very .. clean.. and there is not a single flat worm...
anyhow i know people have troubles with these pests .. this fish is reef safe and very colourful...
cheers
dave