I have a 12 gal tank with a mating pair of young false percs. For the past couple of the days the smaller of the two, the male, has been sort of "mopey". He seems to be going to the top of the tank and sleeping more than usual, although he does seem to like to lie on the top surface of the water under my filter when he sleeps. He has continually done this and doesn't seem to want to move around much. The female, who almost always stays with him in the tank, seems to want to take care of him and check up on him. It doesn't seem to make sense. Is this some normal ritual or is there something deeper I should be worried about?