turn off the lights and keep em off, put some salt and destresser, test water params check if everything is good,
raise temp to 84-86,try to get it to eat with live crickets or something it likes.make sure water is well aerated
if not add air stones/wands & etc, try to keep the aros stress level low as possible. almost every fish ive had floating
or swimming side ways has made a outstanding recovery from doing just these ime. gl to to you and your aro. at
15" it should be a pretty hardy fish dont give up until the last moments. hold him next to a air stone/wand if you have to
or cpr lol XD