JDs are "not" rapid growers, but the more water changes you do, the faster they usually grow. By doing lots of water changes, you get rid of growth inhibitors like nitrate, and fish hormones etc etc.
In nature JDs are omnivores, so any high quality balanced pellet will do.
Algae is a main stay in their diet so I like spiraling infused pellets such as NLS Algamax
The video below is how they live in nature
From tropical rains, the Cenote is under constant 100% water motion and water change.
Near the outlet to caves below, the current is strong and I had to hold on to roots from being swept down. Eden2