60 cube + Tiger Barbs

[Watercaged]

I'm establishing a heavily planted 60 gallon cube and am wondering if this size (2x2x2) is alright for a species only Tiger Barb tank? I know they are very active swimmers and fear they won't have enough horizontal space. If this set-up is alright, how many could I fit? I would like 15-20.
The tank has wood pieces in the middle that will have anubias and buce growing on it.

I appreciate all advice. Thanks!