I do hope you've got a monster upgrade planned for the future
.
My achilles is the most active fish I have ever owned (and I have had a few) and can go 0 to 60 in nothing flat, My tank is a 6ft long, 175g bowfront and he uses it all.( I will be upgrading to an 8 ft long tank in the near future just because of him)
Try and encourage him to eat meaty foods as well as nori and put a tunze stream (or vortech) in the tank for him. Mine loves to play in the current and one of the signs that my powerheads need cleaning is when he no longer plays
