Would you need to black out the three sides if he's in the cabinet? I guess depending on how snug the tank is in there. But I would think it is a safe bet that he's def. just unsure and disoriented from not knowing day from night and constantly being in the dark. I'd imagine it's kinda the same feeling if you've ever woken up at 6pm from a nap thinking it was 6 am. Lol just a random thought, sorry.