[DJRansome]

They grow quickly the first 2 years and more slowly the remaining 6 years of their life span but don't reach their full size until closer to the end of their life. They grow continuously throughout, just start more quickly and slow down as they age.

How big were they when you got them? 1.5" is more of a purchase size than a size after almost a year. Some LFS would not accept fish for sale at less than 2 inches. Are you including the tail when you measure?

 

[DJRansome]

My acei matured slowly as well and I did not get spawning from them for 3 years it seemed like. Whereas the labs were spawning at 1.5".

 

[DJRansome]

Are the snow whites labs, metriaclima or socolofi? Marketing names lack clarity, lol.

 

[DJRansome]

Those spawned early for me...the most aggressive fish in my tank. I did not have the albinos however, maybe they grow/interact differently.

 

[DJRansome]

Try cutting your nitrates in half and see if growth improves.