Fish acting strange!

[corrosive]

Right, i took out my platy last night because he was dying (2minutes later he died) and ever sinse then the other platy keeps hiding and not bothering to move around much... Is he depressed? Or just sleeping... Or is there something wrong?

Also ever sinse last night 1 of my sword tails is acting strange as well hes not moving around as much as is staying away from the other fish just like my platy is.

Thanks in advanced.

Ps - Ammonia: 0, Nitrite: 0.3-1, its starting to come down though.
Ph: 8
Nitrate: 100mg/litre from my test result.

 

[corrosive]

My fish have possible White Spot, and are a bit saw around their gills so are being treated now .