Emergency! Need Help ASAP!!!

so i moved my platy and pictus cats into their bigger tank, most of the
water was their old water, new water was same temp and was treated. the pictus cats stopped swimmin then died. next the platy suddenly did the same. so i took all of them and put them in with my opaline and tetras, etc. most of the platy are now at the top and staying there. wtf happened???

 

did you check your water before adding fish?
what kind of water? it might of had to much chlorine or some other chemical.

 

+1 on above but I note you say you treated the water? I assume with a conditioner, like aquasafe etc?

I think it could be a major parameter change thats shocked and then killed the fish
run a full series of tests on the new tank, or get your fish shop to do it for you

Steve

 

were did you get the new tank from and what did you clean it with

 

new tank was from my golds that i had just emptied and moved.

 

OK maybee not contamination then , was there a undergravel filter involved ?

 

no, a hob filter, same one from their other tank
it was almost an instant reaction of the fish. i moved them back into another tank and 2 cats and 2 male platy/swords are dead this morning, i dont know about the others, the 4 were floating. 0,0,20, API liquid master testing kit