First of all, things are changing WAY too drastically. Salinity levels shouldn't be dropped (or raised) that fast in a short period of time. Also, both species you have are freshwater species, not brackish.
Two things, get a bigger tank or two individual tanks, and the other thing is of course make it freshwater.
I'm tired of getting pointless messages. If your going to start a conversation or ask me something, keep up with it.