Don't feel guilty about the worms. They came with a guppy or guppies at sometime. Nobody tells customers. Indeed if the shop moves their stock out in a timely manner, they may have no inkling of the presence of worms in their fish. After a zillion years in the hobby, thanks to Guppylog people who have brought this stuff to my attention, I am finally both quarantining all new acquisitions (even fish from friends) AND giving them a preventative deworming treatment.

I'm finally beginning to understand the depth of what is facing our fish. Wild fish, especially those collected towards the end of the dry season (when water quality is awful and the fish are crowded together - that may sound familiar) and even pond raised fish are exposed to even more parasites and disease organisms than those raised in someone's aquarium. Then they are stressed by getting shipped long distances in close proximity (in the bag) to other fish, put in central filtration systems in wholesaler's and shop or both. I too sometimes lose new fish. Certainly the mortality rate on new fish, for me, is greater than on fish raised here.

There are days I'm surprised anyone is still in the hobby. (But then there are those other glorious days...)

About a year ago my bride and I were in the Detroit area. They have some wonderful shops there. In New Baltimore, MI I spent more on a group of catfish than I ever have before. They were pretty rare - certainly to me. ;)

The shop had quarantined those wild caught fish in the back and fed them well for a month. That costs them utilities, shipping, import license, food,  a deworming/ parasite treatment, labor for water changes and tank space. We often complain about $7 guppy pairs here, but though I was reluctant to part with that much money, I didn't think that $25 each for fish so carefully cared for was at all unfair.

We may not get what we paid for sometimes, but if we don't pay a "reasonable price" we certainly run much lower odds of getting quality or healthy fish.

I'm just delighted that you are operating at the level of sophistication where you are already doing ammonia tests. That is great. I wish every new aquarists would do that.

I do fear that 1/2 hour with the treatment is not enough. That is probably why you have seen no expelled worms. A week to 10 days is probably more on the mark.

Sigh! If you want to get rid of the worms, you will need to try again! Otherwise wait, hope to quickly rescue some fry and hope that they aren't infected when you put them in separate quarters (which may be whistling in the dark) and let the other guppies die of internal munching.

You have struggled through the Camallanus entries in Immediate Help. I have gotten more info from the "Inkmaker" Charles Harrison than anyone else. I know I haven't read and heard all there is on the subject, I'm pretty sure that Charles would say the same.

http://inkmkr.com/Fish/CamallanusTreatment/

I wanted to get back to you on your water. Rainwater is wonderful for breeding rainforest fishes (even useful in cutting water hardness and breeding some "difficult" rainbowfish). Our pollution and the need for demineralized water is why we have the RO (Reverse Osmosis) unit.

But guppies are from waters with some mineral content and a pH above 7. Even a pH of 8 is ok for them. As secondary freshwater fish (meaning that somewhere wayyyy back along the line, even before they evolved from killifish, they have a marine origin. Most, but not all secondary freshwater fishes (such as Poeciliids, killifish, gobies, rainbow fishes, a lot of other Australian freshwater fishes and cichlids) are pretty tolerant of mineral laden water and a bit of sodium chloride.

I have NO hard evidence of this, but I wonder if putting any medication in almost pure rainwater will not dangerously upset the water chemistry. Indeed your guppies are in danger anyway of "Acidosis" from a plunging pH, just as normal biological processes take place. KH or buffering capacity comes from minerals different from the minerals (iron, calcium, magnesium...) which account for hardness. But in nature they are often found together.  (See IH again or Google Acidosis, I.E. "crazy man's" or "crazy fish's disease.")

If the Inkmaker or GuppyMollie or someone else with an understanding of chemistry and aquarium chemistry can respond to this, that would be great.

Would you (Katastic) Google search Guppylog for miskairal and rainwater or just miskairal water? She got away with her rainwater because it sat in a dust filled catchment basin and had a measurable hardness when she finally pulled it out! She also combined it with local stream water sometimes. ;)

You may find that you will want to add some Rift Lake Cichlid Salts to your water until you get a hardness of about 120 to 150 PPM. If you Google DIY (Do It Yourself) cichlid salts you will find some much less expensive recipes which you could mix up. They often involve a little baking soda, and calcium, potassium and magnesium compounds. Some people get away with Marine salts because they do try for many of the 80 minerals and buffers in salt water, but I still think that is too much sodium chloride.)

Add that mix verrrrry gradually to your guppies so they don't shock. I don't even know how much to suggest, maybe 1/5 of the quantity in the fish tank at a time. The next day the same and then begin to walk up the concentration of "mineralized water" until you are at 50%. Do partial water changes with the made up water hereafter.

I would love to elaborate upon this, but must go.