Guppy Dead, Others In Shock?

[Fraoch]

On sunday i did a normal water change on my 80 liter using all the usual stuff, nothing different but as soon as i put the lights on i noticed 2 of my red guppies werent there. I found them lying on the gravel in the cornor with their bodys frozen bent in a banana shape and not breathing. It really freaked me out, but a few minutes later they were just swimming around like normal again so i figured they must have been in shock from something?. the thing is that those 2 were fine but last night i found my blue guppy dead, he had been absolutly fine before and i couldnt see anything wrong.
I checked the water, all normal, ammonia 0, nitrite 0, nitrate 5, pH 7.6 so i dont understand why he died?
Also my platy in a seperate tank is lying on the bottom under soem plants in the same position as the guppies described above but breathing quite rapidly. She was aswell fine untill now, im just going to check the water on that one but i havnt done a water change on that tank since a week last saturday

thanks for any help

 

[This Old Spouse]

At first I thought you might have forgotten to dechlorinate, but not if the platy in a separate tank is acting the same way. That's very strange. Have you sprayed anything into the air that's different? Hair spray or bug spray, something you wouldn't necessarily think of as toxic?

 

[Fraoch]

im pretty certain i dechlorinated, with the sprays i thought of that aswell but i cant think of anything plus the tank with the platy in is at the end of the corridoor and the 80liter in my bedroom both with quite tight lids
Just had a better look at the platy when it came out to eat and she cant seem to swim preoperly and is very thin, her bottom end seems to sink when shes trying to gte to the surface. I had a platy a few months ago that i bought at the same time as her with exactly the same sypmtoms as she has now and i tryed to treat him for internal parasites but he just faded away and didnt make any improvement

 

[Fraoch]

got stats from the tank the platys in, ammonia 0.25, nitrite 0, pH 7.5 and more than probably the culprit nitrate about a 100 Huge water change tomorrow!!!! One danio also has a small white lump on its bottom lip, fungus maybe?
but now that i found the culprit in this tank how do i go about treating the platy and danio?
and what about the guppies?

 

[This Old Spouse]

Your ammonia reading is more of a concern than the nitrates. The huge water change is in order.

 

[Fraoch]

80% water change done on platys tank, ammonia now 0 but nitrates still high at about 40 so i guess another water change is in order

 

[This Old Spouse]

NitrAtes at 40 ppm is not a problem. NitrItes at 40 would be. So long as your ammonia and nitrites are at 0 you're fine as far as that's concerned.

 

[Fraoch]

ok yeh their all fine, now how to treat the platy and danio