Something in the bottom of my aquarium

Question
Hi! I have one pearl guarami and one blue one..I'm not sure of their sexes. They have been doing fine, yesterday I noticed the pearl one (Charlie) is staying close to the bottom and protecting what looks to me like a ball of brownish cotton. I'm not sure what it is..my PH level is 7.0. It is not attached to my fish at all..it's just in the bottom..Charlie will come up to eat..but then right back down..Any idea what that is in the bottom?

Answer
Well....normally when fish are protecting something it's eggs. The only problem is that Charlie's specie of fish (Trichogaster leerii) breeds at the surface. And Charlie's tank companion is related to Charlie but those 2 cannot cross breed. Is the color of the "ball" the same color as the food you feed to your fish? If so, it could either be uneaten food or poop. In either case I would use a turkey baster to remove it.
One reason for him being on the bottom (this being strange since this specie should be dwelling at the surface or mid level) could be that he's getting picked on by his tank mate. Different species of gourami will pick on eachother. Your Blue gourami is the same specie as the gold gourami, the cosby (also known as blue or opaline gourami), and the 3 spot gourami.....they are all color morphs of the same fish. This specie tends to be a little more aggressive than the pearl gourami and so he may be picking on Charlie to the point of making Charlie hide out on the bottom of the aquarium.