Some people will give there fish a prophylactic FW dip .. some a formalin bath .. most don't give them anything. I give my fish a formalin bath .. helps against brooklynella and many minor exterior parasites like flukes etc.
Here's a link discussing FW dip.
http://www.petsforum.com/personal/tr...waterdips.html
Heres a link discussing formalin baths
http://www.petsforum.com/personal/tr...alinbaths.html