Bart k.

If you're seeing what I see sometimes, it looks nothing like any of the worms I've seen.

I personally think it is some sort of after-birth material that the females jetisson after finishing.  It is pale white, stretchy and can get an inch or more long.

(No, it isn't the same as the white stringy poop when they've got bacterial problems etc).

I usually see this after they've finished.  But I've seen it part way through on some females that I had in nets.

The fry were fine until about a month after birth.
Several of them began showing a little "fluffy" almost cottony looking thing sticking out of them.  Those ones got very emaciated.  Some of them almost looked like little furry udders and were half as large as the fry.  
Those ones all died.

A few weeks later the remaining fry got incredibly swollen and hard looking, and I could actually see something white and ropey pressing against their insides.  I immediately thought 'worms' and tried several different remedies (Parasite Clear to treat the tank, fish food treated with metrodinazole, and lavamisole, etc.) but they also all died.
Also, EVERY single pet store in my area that carries fish products (9 stores total!) had expired Discomed, which I read here is the de-wormer of choice!  I'm not sure how effective expired meds would be... I believe the dates were Feb 2004... but wasn't willing to spend the $15 or so.  

NONE of my fish (30 of whom are now deceased) ever showed anything that looked like camallanus red worms.  Just the large fluffy blobs, small bubbles, and then the swelling/ropey insides.  

I was never able to figure out what happened, or what to do about it, and I'm still too freaked out to spend money on new fish.

It actually has been a little while since this has come up. For those here six months ago, there is probably a collective groan though. ;)

If you saw the actual worm hanging out the fish's anal vent, here are two pictures of it so you can identify it as a Camallanus worm or not.

http://www.rhusmann.de/aqua/bilder/camallan.jpg

http://www.max-discus-dream.de/mddnew/Images/Erreger/camallanus3.gif

If it is, click to the Guppylog Quick Links fast and read all of the entries under Camallanus. Your tank will need to be treated with a dewormer. Don't take anything (hands, nets, fish, siphons) from that tank and out them in another tank. The good news is that most of the fish will respond positively to treatment, though the one with the worm may not survive the process.

I really hope I'm wrong. But for the sake of your guppies, please take a close look at that object extending from that one animal and compare it to those references - quickly.

If that is a Camallanus worm spreading youngsters, unless you are on the West Coast, the stores are probably close to closing or closed and you can't get a dewormer tonight. Read the Quick Links. get a good night's sleep, and plan on getting a dewormer tomorrow and treating the tank when you get home.

Hope I'm wrong. That is one of the first questions though to ask in such a situation.

When I was a kid and spent more time watching the fish than corresponding about them, I recall the shock that accompanied espying a female guppy that  had swallowed a human hair a little over an inch long! Perhaps she mistook it for a Dero worm. Thought surely she would die. Over the course of a day or so, that hair began to work though her. It really was gross watching the hair go into her mouth and extend out her vent! Somehow the guppy's intestine contorted enough to let that hair go through.

Of course parents of small children and keepers of over inquisitive dogs could have told me, "all things must pass." ;)