Freshwater Flounder

Question
I just obtained a Freshwater Flounder from a friend who couldn't keep it anymore, he had it in freshwater. But now that I'm reading up on it, it says it needs to be kept in a tank with about a 1/2 teaspoon of salt for every gallon.

I have a 20H Aquarium with the following:

7 Zebra Danios
1 Balloon Molly
1 4in Angel fish
1 2in Angel fish
1 Opaline Gourami
and the flounder...

If I add the salt will that hurt my other fish that currently live in the tank?
Also I am soon to have a salt water tank, can he eventually moved to all salt?  

Answer
Hi Krista,
From what I know about the fresh water flounder, they actually need 2 teaspoons of salt per gallon, and you must increase the amount of salt as the flounder grows in size.  Now there is no problem for the balloon Molly who can live in salt water, and should when it reaches adulthood....however, the angel fish, gourami, and danios can take no more than a teaspoon of salt per 5 gallons of water.  The amount of salt that the flounder needs, would surely not be good for your fish.
The trouble here is that you must increase the salt for the flounder as it grows, which means it can eventually live in salt water, but you will have to bring him there slowly.
Also just want to mention, that they do not like flakes, but meat, so you will have to find the appropriate food for him.
Hope this helps
Lynda