Compatible Fish? / guppies

Question
I have a well established 55 gallon aquarium. It has a black banded leporinus, a blue gourami, a pleco in it. I recently added some fancy guppies, a couple of platy's and 2 dwarf gourami's to it. I followed the acclimation procedure, taking over an hour. Over the weekend (office tank) all three dwarf gourami's died and disappeared, all but one of my female guppies died and disappeared and the platy's are fine. Could the blue gourami being eating them? Or could they be dieing and then being eaten? I tested my water and there is no ammonia, no NH3, pH is 7.2, temperature is 78 degrees, ect ect in other words the water is fine and well within all of the fishes ranges.

Answer
Hi Alysha,
It is always hard to find the mystery fish killer but I think there is a possibility that it could be your black banded leporinus. I don't see how any other fish could be doing it. I am sending you a website and I think you should read the article on this particular fish and then decide what you think.
http://www.fishforums.net/index.php?showtopic=34589
I hope this solves your "mystery" as to where the other fish disappeared to.
Hope this helps,
Karen