whenever i am cleaning my tank they come up to my hand
i always pull out, but they are so slow you can see them coming as long as you pay attention i think you would be find. When mine were real small they were in a 20 but they outgrew it real fast. i have a 50 now and they are soon going to be outgrowing that.
well if you put your hand in at feeding time, your asking for trouble. Hell your arowana will bite you, a lot of fish will. 20g is too small, and would be too small for any arowana so you will need to upgrade. Most gars get pretty big though.