Just lost mt stingray and gar. Ideas?

[meBNme]

I got them both at the same time, along with the sturgeon, and an algae eater.

The gar has some splitting and damage to his tail, I thought was just from catching and transport etc. Then he developed a fuzzy mold like white/clear substance on the tip of his mouth/beak/snout/whatever. The day I noticed that was the morning of day 4. Evening of day 4, he was a floater.

The stingray, never ate anything, and started flopping and falling over upside down on noon of day 5, was dead within 2 hrs after.

The sturgeon is doing fine, swimming strong, eating like a hog in a cake factory, all the other fish are doing great.


What happened?

Is it likely the gar had beginning stage of disease when I got him, and it just took the stress of moving and 4 days to off him?

Is it likely that the stingray was overstressed from his shipment to the LFS and then to my tank within a weeks time, and just croaked?

I put em both in ziplock backs and froze em, for store warranty purposes.

Any ideas/comments/advice?

 

[jetajockey]

how big is this tank, how long has it been set up? Have you tested your water at all?

 

[meBNme]

150g, about 3 mo, yes.

PH = 6.8 to 7.0
Ammonia = 0 (I did see traces of, but less than .25 just before opening the bags. Next day was 0.)
Nitrite = same as ammonia readings.
Nitrate 40


My well water is: (in the same order)

6.4
0
0
30 to 40

More details & info is in my bio.

Thanks for responding.