Dither Options?

[shenzhenluohan]

P. denisoni, denison barbs are really colorful and big enough they shouldn't get eaten.

 

[Aqualoon]

Alright, so going to do a single GT I believe in this tank, with that in mind what school size should I shoot for on the Boesemani Rainbows? I was thinking 12-15, would I be able to get more in here? Would love to have a nice big schooling of fish.