disease?

okay something is wrong with my tank and im starting to worry alot over it. one of my panda corys has died a few days ago (im assuming because of the body i found with just some of the actual body attached to the skull) and now one of my albino corys is acting strange by swimming at the top of the water for long periods of time and its also being lazy, like not moving at all. what could be the problem? if it is ick, i dont see any spots on the bodies of the fish. dont know what else there is out there but can somebody help my fish?:help: the others seem fine. if anything the electrin yellow cichlid is rubbing against some of the rocks once in awhie.

2 temple ruins, gravel, some elodia, a slate rock cave, some fake bamboo and a buddha statue. 2 filters. 1 bubble wand.

the nitrate and ammonia levels are fine. i just changed some of the water (10%) and i just changed the filter cartridges. they are looking fine right now but id give it a couple of days. im not the one to celebrate too early. before this whole incident happened, i had a really aggressive neon gourami that would pick at the other fish in the tank. the corys fins were all busted up after a while, so i took him out and put him in a seperate container to give to my friend. could it be ick? i dont have my camera handy, but the water looks fine and there seems to be nothing wrong at the moment with anything in the tank. i just cleaned the temple too by washing it out in some hot water and scrubbing it. could i do anything else?

Sorry for the drama. it seems like all of the corys are going in the same spot and i even seen one shoot out some semen onto the glass so im guessing its egg laying time for them. still gotta wonder why the panda died though. you have to consider the fact that it was always small and pale looking ever since i got him a few months back. the rest of the fishare doing fine now. im just looking foward to seeing some little catfish in my tank. ill post back tomorrow to tell you guys how they are doing.