Why are flatworms so bad?

[leahski]

reading different people talk about flatworms has made me kind of inately afraid of them. but i realized i don't even know why they are so bad?
i've read that one species eats acropora or something like that, but in an all softie tank, are they that much of a threat? and how many do you have to have before you start doing more than just hope you're vacuming them out during water changes?

a few weeks ago i noticed a single white nudi on my rock and removed it promptly (inate fear!) before i knew that they were harmless.
then i noticed a tiny light brown/rusty colored kind of "ghost-shaped" worm on my glass. there have never been more than like 3 on the glass at a time however, so i never really considered it a problem. but i just introduced some new zoa frags last night and today i counted 13 of the same little red ghost flatworms on my glass as well as two yellow ones that seem to be the aceol planaria (sp?) kind from the sticky note.
oh yeah, it's an 8g biocube, been up and running for about a month and a week. only livestock is CUC and the new frags.

so i guess my question is, is my inate fear of flatworms justified? are they going to rampage my tank and kill every living thing i put in there? if it's not that extreme, do i still need to take greater measures than just vaccuming?

your help is GREATLY appreciated!
Tori

[prow]

they are not so bad if you dont have acros. the one that eats acors is white/opaque. thats the biggest feared one only becasue it eats acro tissue. the other is brown/rust and if enough food "nutrients" their population explodes quickly. they cover rock and coral preventing growth and may even cause damage. but usually they die off if tank parameters are good. in a nano i would get rid of them ASAP-even if they dont cause damage to anything in the nano tank they will take over and be everywhere. it would suck to look at your tank and mainly see these flukes everywhere.

[BEELZEBOB]

there are many different species of flatworms, all of which eat different things.

the eat corals directly, smother softies, etc.

they also breed like rabbits.

when they die, the releas a horrible toxin that can kill every single living organism (down to bacteria) in your tank if a large enough population dies in your tank.

and they're ugly

[leahski]

okay, i've done some research and decided that my flatworms are probably Convolutriloba Retrogemma. if you go to this link: Worm Hitch Hikers and look at the very bottom at the flatworms, mine are identical to the second picture.

so to get rid of them you recommend just siphoning them out when i do water changes? there really aren't that many and i haven't seen any on my rocks/corals (although they're so small i don't know if i would be able to)

[prow]

that sounds like a good plan.