New rainbow snakehead tank

Hey there, new to the site.

I recently set up a 29g tank and have two rainbow snakeheads in it. This is how this tank will stay, (no more fish)
and it is currently filtered with a 45g fluval canister (2 trays of biomax, and top tray has carbon, but could put any additional material in the tray.

I also have a 20g tank set up as a community tank, and my intent is to breed/feed the guppies that are in it for use as feeders.

I understand the varying opinions on feeders but this is what it am doing (my snakeheads are also eating frozen bloodworms)

Basically I'm asking for tips on keeping rainbow snakeheads, optimal water conditions, (I want to really bring out their colours) and how best to feed the feeder fish, and how often to feed live vs bloodworms

Thanks for the tips on foods,
The manager at my
lfs keeps a pair in a 29g and he said they should be fine. He also recommended strictly live good but I guess not the best advice.

would crickets be a good food choice? I have access to them quite easily from the lfs.

im keeping the tank around 22-23 for the summer and was going to drop it to around 18 in the winter, how long should this winter period be for the tank?

from what I understand they are illegal to buy and sell in Ontario but Nova Scotia permits them, my legs ordered in three as a test market and I was lucky enough to get them.

Is there any way to bring out their colours, how
much will their color change from now? They are about 3 inches at the moment, quite young.

As far as a pair, I don't know the genders. Both same age and
appear to be from
the same spawn. (Same markings)
i could pick up the third one my lfs has in hopes a pair forms, and then sell/give away the odd one out?

Oh, they seem to get along, frequently laying on eachother.
had one fight where one tried to enter the cave while the other was in it, but was only a one time thing and they have since been getting along