content: I have used this aquarium in my daughter's crib since she was two months old. She is now 10 months and still loves it! More importantly, when we lay her down and press it on, the music signals to her that it is time for bed. She willingly rolls over to look at it and eventually falls asleep. She used to press it on herself in the middle of the night to go back to sleep(when her crib was lower and the aquarium was more accessible). I would reccommend this soothing toy to anyone and suggest to start using it early on. The only modifications I would make would be a remote control for parents to turn it on without entering the room(it only goes for 7 minutes) and maybe longer straps so that when the crib is lowered the baby can still reach it.