brackish or freshwater?

Question
I have a Pleco, a flying fox, a couple cories, mountain minnows, guppies, a platy, and an angel fish in one tank. Lately i added four chocolate gouramis, 2 of which died. One of the two that are still alive had ick(which was treated), and the other one is hemmoraging quite badly. I tried to treat it, but nothing happened. The ph was quite high, 7.5, and the guy at the pet store told me that this was probably the reason for the hemmoraging. However, i lowered the ph to around 6.2, but it hasnt seemed to do anything, and i have to treat it every day just to keep the ph down. I've heard somewhere that chocolate gouramis are brackish water fish? is this true? and what is brackish water? I would really like to know why they are going so badly. any suggestions would be greatly appreciated.
thanx

Answer
Hi, it really importand not to buy gouramies in such a wonderfull  tank because they carry bacteria ,gouramis are very suseptable to much bacteria and brakish means a little salt in the water which is not true.If i were you i would remove the gurami it may give disese to all your fish.THANKS!