Id say that a 150 (normal dimensions) is too small for an arowana. And may be too small for 10 RBP, i think they would fight over territory, 1 rbp for every 20 gallons is a good rule, but 10 could work.
I like a big variaty of fish my self . I have never owend a fish fore more than
18 months I Am So Glad I Did Not Start Off With Piranha ." Save The Best For LAST .!