Long Fin query

My first batch of lf hatched roughly the same time as a batch of sf albino.

The albino sf are triple the size of the lf the same age.

Even some of the fry that are not exhibiting lf characteristics but from the same brood are nowhere near the size of the pure sf strain.

Is this normal ?

I usually sell the alb sf at about 2.5 - 3 cm which to now has been roughly 3 months.

I am wondering how much longer it will take the lf to get to 3cm ?

yeah, they do take longer to grow. I find they take an additional month or two to get to 3.5cms (size i sell them)