When young 27's don't have the black white banding on their tails
Like this borrowed from evolutions on arofanatics
View attachment 902585
Price as mentioned but some vendors or LFS charge a lot for 190's ,191's and 330's
Teeth pattern, body colour, pattern/stripes, body shape
It's best to post an ID thread if you're not sure. Sucks to pay more a fish than you should
i got give credit to Jackson for pointing that out about the banding on the tail fin.