by sevenyearnight on Tue Nov 22, 2011 5:42 pm
The water has to have sufficient KH and GH. Making brackish water raises the KH and GH, but are mollies found in freshwater (as well as brackish of course) in the wild, but the water should probably be very hard water. I'm sure everything varies, but mollies are fine if the KH/alkalinity and GH is adequate, but it would be kind of silly to not just put them in brackish since that would be a very simple way to ensure those water requirements are met. That is unless having brackish water somehow would adversely affect something else in their tank.