a PH of 9.0 is absolutely WAY too high for tropical fish.
Have u been adding water conditioner to your tap water? and what about bacteria for your filter to get your ammonia/nitrate levels down?
if you havent been adding anything to the water dude itll be the chlorine thats killing your tropicals.
these things take time.. dont add too many fish at a time, we only had 6 very small glowlight tetras to start off in our tank to cycle it,as the ammonia will rocket if you add too many too soon.
Even the best fishkeepers lose fish, make sure you keep upwith waster changes every week say 20 - 20% until the tank has cycled.
Put your coldwater fish somewhere else.
Goodluck!
Starry^