Your rays stopped eating due to stress, nothing as complicated as some might have you believe. A drastic shift in any water parameter has the potential to stress any fish, which certainly would include P14 pups.
Start looking for signs of other health related issues.cheons also acted up came from the same batch of p14 s as yours.
FYI - I saw this entire batch of rays when they first landed, and for the entire 4 weeks that Bret had them before they were released for sale.
Every last one of these rays were eating like little pigs from day 1. Every last one of these rays were as healthy as one could ever hope for from day 1, and continued to be for the entire time that they were in Bret's care. To imply that some of them may have had gill flukes, is absurd.
Not only did all of these rays go through a rigorous QT regime from the supplier (who probably has the best reputation in the biz) they also went through "weeks" of another QT regime after landing here in Canada.
Anyone that knows anything about gill flukes, and the manner in which these rays were QT'd prior to sale, would understand that IF any of these rays had gill flukes, ALL of them would have shown symptoms within days, as they were all kept on the same QT system. It's fine to speculate, but in this case it's based on zero facts. The chances of gill flukes in any of these rays when they left Bret's facility is about as remote as getting hit by lightning while driving down the Deerfoot. What happens after they leave Bret's facility is anyone's guess, which is all I've read here, a bunch of wild guesses.
With regards to Calgary water, pH, fluoride, etc.
Here's a good place to start.
http://www.calgary.ca/portal/server...er+services/Drinking+water/Drinking+Water.htm
and here.....
http://www.calgary.ca/docgallery/bu/water_services/water_quality/2010_Water_Quality_Report.pdf
All glacial fed tap water undergoes seasonal fluctuations in PH, TDS, hardness, etc, this is perfectly normal, the same thing happens in Red Deer, Edmonton, and numerous other cities & towns in AB. But these changes aren't as drastic as being implied in this discussion, they happen gradually, over days/weeks, not overnight. If the pH in ones tap water isn't checked correctly (only after allowing to sit overnight, which allows the C02 to escape) even that will have a major effect on ones reading.
Fluoride is a natural component of the Bow & Elbow Rivers, Calgary only adds enough fluoride to bring the natural level up to 0.7 mg/l, and only when required, to which they have been doing since 1991. They actually lowered the amount in 1998, from a target of 1.0 mg/l, to the current level of 0.7 mg/l. Hardly anything to be concerned about.
And unless Calgary is hiding the fact that they use chloramine in their system, they do not add ammonia to their water. Calgary water is filtered via several methods, and disinfected via chlorine, ozone, and UV.
If you read that water quality info above it's clear that different parts of Calgary can & will have different water parameters depending on which facility is supplying your part of the city. In some cases it can even be mixed, but none of this has any bearing on what happened in the OP's tank, at least that seems fairly obvious to me.
Good luck with your pups glamit, hopefully the remaining 2 bounce back soon.
Neil