I have two oscars, a 17cm one and a 27 cm one, the 17 cm one always sleeps right on the top of the water lying right on its side, yet the bigger one stays at the bottom and just stays still. are both of these normal behaviour? ALSO my oscars fight at night, never in the day, theyve lived toghether for a few months now and sometimes when im in bed (the tank is opposite my bed) they wake me up with splashing then i turn the light on and the smaller one is on its side at the top again. and help? is this normal? the fish never really have signs of harm but the little on did have a scraped mouth not long ago but that could have been something else apart from fighting..