Unsuccessful using Chloroquine Phosphate

[flfireman1]

So I had been treating fish with velvet using Chloroquine Phosphate. Initially I obtained it via EBay, which that didn’t pan out. I obtained CP from a different seller on eBay with same results. I attributed my failure with having not used pure CP or pharmaceutical grade CP.
So I finally was able to get a script for CP and ordered it from diamondback drugs. This time symptoms cleared up very quickly but after about 2 weeks I started seeing symptoms again. I then happened upon a YouTube video of a fish vet from here in South Florida who was discussing the use of CP. He mentioned that if you run into a tough strain of parasite like I did he advised to do a 50% water change and to re dose CP. I tried this again and after about two weeks had fish swimming up against the powerheads again. I did freshwater dips to rule out flukes and found nothing

I also read somewhere that CP degrades with light and that it needs to be redosed every week. I just find it scary to be adding so much medication without being able to test for it.

Am I the only one who has had issues with CP?

I eventually went back to Copper and fish appear fine after 4 weeks in treatment.

 

[Brett newell]

Yes light does degrade it. Personally I do a 50% water change 2 times a week in qt for 5 weeks and with each WC I dose 75% of the dose back to ensure it stays above the 40mg per gallon. And if my math is correct i should never go over the 80mg per gallon that most fish can handle. I use NLS ick shield powder. I tried to get a script, spoke with 3 different vets and they all said "we dont treat fish"

 

[Humblefish]

How long has your QT been setup? Biofilm will degrade CP (and other meds) in a long-term QT: https://www.reef2reef.com/threads/qt-and-biofilm.292878/

 

[flfireman1]

During the treatment of CP I emptied the tank, cleaned it up, dried it and redosed the CP. Did this a couple of times. Since I also treated the fish in formalin baths and wanted to reintroduce them to sterile QT. I had already read the biofilm article.

 

[Humblefish]

During the treatment of CP I emptied the tank, cleaned it up, dried it and redosed the CP. Did this a couple of times. Since I also treated the fish in formalin baths and wanted to reintroduce them to sterile QT. I had already read the biofilm article.

One possibility is since these fish had repeatedly been treated with subtherapeutic CP, they had developed a resistance to the drug by the time you finally used pharmaceutical grade CP.

 

[User]

One possibility is since these fish had repeatedly been treated with subtherapeutic CP, they had developed a resistance to the drug by the time you finally used pharmaceutical grade CP.

This is the most likely scenario (speaking as a professional microbiologist and parasitologist).

Stay away from eBay meds. You have no idea what you are buying and since it can’t be tested for by the Hobbiest, I’d bet a huge proportion of eBay CP contains little to no CP in the formulation that you buy.