See post #6 in this thread about the heater. As for the food, I tried in my main tank, but the bloodworms go into the sump too fast. So it is extra food.
The fish seem to like them. It also gets the Oscar to move a little faster.
The fish mainly eat Hikari Gold and Staple, Omega One flakes, Aquadine flakes and sinking Hikari pellets. Occasionally they get shrimp, earthworms, and feeders.