About 1"-1.5" a month until he reached roughly 8" and now he's slowed down a bit but still growing fairly fast.
Diet:
Hikari Gold Large Pellets
Massivore Sinking Pellets
Peas
Blood Worms
Beef Heart
Crickets
Algae Logs/Wafers (supposed to be for the tankmate
)
Few Giant Danio, Clown Loach, Silver Dollar (Not on purpose, obviously the rest of the school was moved there after)
I honestly did keep them for 2 semesters in a 10 gallon, they probably didn't get fed enough and a proper diet... I was a dumb college kid back then and 10 gallon was the max they allowed in the dorms.
We've all made pretty obscured rookie mistakes when first getting into the hobby. At least you know better now.