Some of our fish have fin rot and white spot, it is a two week old tank. We have just put some white spot treatment in, but mis understood the instructions and put five times too much in. we have changed fifty percent of the water but our little catfish keeps floating on the top then coming to life again, all the other fish are a bit dopey and the frog keeps going mental, also our fighter has just died of fin rot, boo hoo. any sugestions of what to do now ??