Amatitlania nanolutea - Pair at such a young age?

In Early Nov. I purchased 7 Nanolutea juveniles from the WetSpot. Largest about 1 inch.

Now three months later it looks like a pair has formed. The male is almost 2" and the female a little over 1",

What amazes me, at such a young age a pair has formed and they are lit up in breeding coloration.