Your question is a very important one and one that we should revisit from time to time. Diagnosing these things in a forum can be a tad
tricky. Wayyyy less important than, but sort of like coaching child birth over the phone. ;)

Were the only things, which left the female guppy, these little red wormy things, that looked a little bit like blood worms? Did they actually
leave her body or just extend out of that vent?

Call up another browser page and go to Google. Click on the image search and search for Camallanus. Do any of their shots resemble what you are seeing with your female?

A related question, not because we wish to engage in shop bashing, but were your guppies purchased at a commercial enterprise? Don't mention names, but if they were from a shop, was it an independent (privately owned) pet shop or a big box store and part of a chain?

Also, just because I'm curious (and will explain later if you don't pick up why in Immediate Help), does the source shop have a central filtration system, where water is circulated to and through a central sand filter?

Also, would the water be circulated from one tank to the next (1 to 2 to 3 and on and on) before going through the central filter?

Those central filtration systems, once established, are great at running a developed nitrogen cycle through all their aquariums - even
for newly set-up tanks. However they also, especially if plumbed in a circuit, are a great way of spreading pathogens and parasites from tank 3 to tank 4-5-6....130.

I'm guessing, if the only things you are seeing are those little red things, is that your female guppy in infected (infested) with Camallanus cotti, a nasty bristle-headed worm. What the hanging worms are doing, is releasing a LOT of live-born baby Camallanus. Their stage one larvae are mostly tail. That tail thrashed around like any other agitated worm and is verrrrrrry attractive to hungry fish (including almost all fry) and even invertebrates such as Cyclops and Daphnia.

They swallow those twisty little rascals. Many of those worms metamorphosize into the next stage larvae and grab a hold of the side of the fish's intestines. They then spend the next three months or so, sucking blood from the fish, growing, mating and getting ready to release their young into a fish tank or (in the wild) river, pond or lake.

If the fish they have parasitized gets swallowed by a predator (including humans if they don't cook the fish well or clean out the viscera) those worms have the amazing ability to survive the acids and digestive enzymes in the stomach and latch onto the intestinal wall of the predator.

That is very debilitating. Some fish are never able to produce many or any young again. Guppies and livebearers are just some of the many, many fish vulnerable to Camallanus. There are about five Camallanus species native to North America, but the East Asian C. cotti (which has also gotten loose in many parts of the world) is the most common in the aquarium trade.

And EVERYTHING in your tank has been exposed to them. Leave the snails in there when treating - although you may want to do partial (25-45%) water changes after a few days and returning activated carbon to your filter, if you use it. If you don't remove that treatment with in a week or so, you may find that the snails (possibly a vector for various fish (and human) diseases and parasites are beginning to die off.

I would recommend taking any activated carbon or other resin out of your filter and treating the entire tank with either a commercial treatment designed to take out internal parasites or a specialize treatment. (See below.) Look for such an item in your pet shop.

It should have an anthelmintic (or antihelminth = anti-worm treatment) in it. As a rule these are much less devastating to a tank's nitrogen cycle than antibiotics. The drawback to the anthelmintics is that certain anthelmintics are only effective with certain kinds of worms and other parasites and not effective with others. And if you get them from a Veterinarian, they can
be very expensive. (In a hurry some years ago, I asked a vet to mix a batch of Praziqualtel from the dog de-wormer Drontal. It ran me three figures. Commercial med mixes or the Inkmaker's offerings (see below) are much less expensive.

Levamisole and Flubendazole are among the anthelmintics that have proved most effective again Camallaus. Ivermectin probably would too, but is harder to get and trickier to use.

I know that mebendazole has been mentioned too as a treatment for Camallanus (it is in the much cheaper Fluke Tabs) but I don't personally know that it works. Also, you will have an organophosphate also included in Fluke Tabs. Only buy the quantity of Fluke tabs you will need this next year; the shelf life isn't real long.

Discomed from Aquatronics (pink package) contains Levamisole. Levamisole sometimes is marketed as Ergamisole and also is sold by vets as Tramisol.

I just looked at a package of Jungle Labs' Parasite Clear (the bag buddies version - I was given it in a raffle). It has a lot of stuff good at taking out external parasites such as anchor worm (really a copepod or small crustacean) but the included anthelmintic is Praziqualtel, which is useless against Camallanus. So read the ingredient list carefully with each parasite treatment. If you have had a long day, you may want, before hand, to slip a small magnifying glass into your pocket to help you read those tiny letters. :)

Don't let "them" sell you something that doesn't have one of those recommended anthelmintics. I would hope no one would. But if they do press the issue, under the odea that any anthelmintic will work, maybe offer to just go into the parking lot and throw the contents of your wallet up in the air. ;)

Charles Harrison, an accomplished chemist and fish-head, has gotten quite into this. He sells some of the anthelmintics on-line fairly reasonably.

A lot of aquarists owe him for the effort. Read his articles when you can. (If you Google Charles Harrison and Camallanus you will get more.)

http://www.inkmkr.com/Fish/

I recently picked up an international shipment of levamisole and flubendazole on his behalf (in Chicago). It was sent to him in the St. Louis area, via a mutual friend, this last weekend. He has gotten pretty serious about having these items available to aquarists.

This topic has also come up here from time to time. When time permits, please click on Immediate Help (to the upper left of the page) and scroll down to the posts on Camallanus. Some other times, you might find many of the other Immediate Help items of use. I still do myself.

Hope this is helpful to you and your guppies. Please let us know if you guppy does have Camallanus.

By the way, most experienced Guppylog people just submit diary entries. Those posts get to the front page and everyone's view a lot quicker.

If you wish to re-submit your log above as a diary, I'll copy my comments and also submit them there. (And then I'll delete this submission.) You may get other comments that way.