Originally Posted by nicetry
Ever seen a full grown niger? Well over a foot and very active. Much too large for a 90.
If you don't want anything else in the tank, an undulate would be a good choice.
A Picasso would work for awhile but IMO need larger tanks as they mature.
I strongly agree. Niger's grow to almost 18" long.
Unfortunately, there's not too many species of Trigger to choose from. Undulate, as nicetry said, is about the only one. They're also one of the most aggressive Triggers, so it's gonna be a species only tank.