feeding

I just purchased a male dwarf gourami and put him in my 30 gal tank.
I have various fish in this tank (cories, upside down cat, tetras,
even a tiger barb) that all get along just fine (even the tiger barb
believe it or not!), however I am curious about feeding.

What's the most efficient way to feed these variety of fish? Certain
type (flakes vs pellets,etc) or method in how you introduce it to
them?

More specifically, I'm concerned about my gourami. He's new to the
tank (3 days now) and he hasn't seem to eat anything yet, that I can
tell. Any suggestions? Might he be getting food and I just don't
know it?

If you need more info to answer, just let me know. I'm somewhat new
to this hobby (4 years).

thx in adv