Well as they're top feeders it's natural for them to prefer taking food there, not on the bottom. When a bit bigger and more confident they'll feed more readily from the bottom, but esp. when younger like yours they may often be more reluctant to do so (I think they just feel more vulnerable).
Both of my Aros will pick up the occasional piece of food that hits the bottom but I can see they're not as comfortable and also I don't really want them feeding off the bottom -- whenever they do it's a quite awkward pick up, not from straight on but from the side and they have to tilt their heads weirdly. Usually probably not a problem but I'm worried they might damage their mouth or barbels in doing so, esp. because my tank bottoms have edged glass bracing all around.
As such, and this might be your best solution until your Aro gets bigger and more confident, what I do is spoon in just 1 or 2 pieces at a time. Aro smashes them then comes around for more. Repeat, repeat. It's a somewhat more time consuming process but means very little if any really hits the bottom (which means less to clean up or cause water issues after feeding).
