Originally Posted by paytheplayer
Thanks for the help! I read this from one of those links
Is this true?
Well the guppy originates from fresh and brackish waters in South and Central America but as bearwithfish said it's not a requirement. They do better in brackish but can live in freshwater. Brackish is where salt water and fresh water meet. The only way to have a truly brackish tank is to buy something called "instant ocean" its marine salt, 1tbsp per gallon will create a better living environment for ANY livebearer.And a lot of LFS's don't keep them in brackish water. We've always kept ours in freshwater but after talking to my bf today he's thinking of raising the salinity slightly to encourage the females to drop their fry. The salinity has to be raised in increments not all at once or it can kill them.
To convert to brackish you need to do this slowly, by disolving 1 tbsp of teh salt in some water (about 1 cup), preferably from the aquarium, stir it up and pour it in. NEVER ever put the salt directly into the tank, it burns the scales and recovery is from that is hard and sometimes impossibe. In another few days repeat, repeat until you have the required amount of salt. I've heard some people say don't use kosher or table salt and some say it's ok, so that's a foggy area for me.
Keep in mind also the salt may not be good for certain freshwater plants.
Here's a link to read over explaining all that and the types of salt to use:
The Skeptical Aquarist