The bigger your tank, the tighter they are going to shoal. 
Throw in a few preds. too, that really gets them going!! Pretty much most of your tetras are going to school/shoal. Hatchetfish are cool to watch!!
Throw in a few preds. too, that really gets them going!! Pretty much most of your tetras are going to school/shoal. Hatchetfish are cool to watch!! 