I have 2 neon tetras and 2 glo light tetras and 2 snails in a newly cycled 10G. I noticed the cory wasnt moving very much the last 2 days and this morning it was dead and I dont know why. The levels are all ok as of yesterday. I will check again tonight and see what they are. I am hopeing it was just sick when I got it and not something that was in my tank that did it.