I have had arrowana several times in the past.
One of my all time favorites .
Knowing better now I will probably never have one again unless I build the basement 2-3k tank.They don't belong in our tanks IMO
. I always had mine a 6' 135 or 180 and just don't think that is enough..
I had 6 juveniles back in the 80s and 1 always owned 1/2 the tank while all others were kept in check.Removing the alpha only resulted in changing who swam on other end..Lasted 6-12 months before I had sold /traded all in.They started at 2 inches and were 8-12 when sold.
Last time in my 180 I obtained a 3-4 incher and it was all of 10 inches in under 6 months and ended up succumbing to some illness . Too small of a tank [stress] was my final verdict as he was the only victim.He was housed with tetras and rainbows..The tetras did not do well either but they passed healthy I am sure .
My first aro was all of 16 inches and he was in the 135 with a larger snakehead ,clown knife and red and black pacu pairs !
Talk about over stocking..Been there...
Although I consider them the most graceful fish to watch I just think most of us can not do justice for them..