Help! ammonia spike with fry

[Creat]

Like usual I checked my tank tonight ( i do it twice a day morning and night). And I had a massive ammonia spike, some of the fry are on their side, one dead. So I did I 100% water change netted all the fry (there were like 12) and now their floating in their container in the new fresh water with a little aq salt added. Whats the best way to acclimate them to totally new water? I dont want to kill any more :(
And I wish I knew why this happened.. I do 50% water change a day then an 80%-90% at the end of the week, they are in a 10 gal too filled to about 5 inches. There is no filter only and airstone.
Please help with any ideas? anything I should do before I release them I'm slowly adding water to from the tank to their container...

[Creat]

some seem to have a hard time swimming off the ground too, is this caused by something else also?

[indjo]

If you have an ammonia spike IMO it's not wise to do 100% wc. You should have done a 90% instead and use a drip system or add new water very slowly (like an hour or two). You see with total wc, your fry would have been shocked and the weaker ones often doesn't make it.

I would take some of the old water and put the fry in it while I clean everything in the tank. Then put water and fry in the tank and refill new water with either a drip system or very slowly. If the ammonia level is still high, do more wc the following day, and refill the same way.

Good luck. Hope they make it.

[Creat]

Thats basically what I am doing they are still in the old water now but sense adding new water slowly its probably about 50% new... and thank you