this may be a stupid question but if Im feeding my CNB feed and RES don't eat feed and my pond is brand new with not much of an established food chain what will the RES eat?

Just because the RES don't come to the surface doesn't mean that they aren't eating feed. Mine pick up pellets off the pond bottom.

Assuming you have some snails that is what RES will eat. Some of your RES might start eating feed with your CNBG as well, 20 percent is a good guess.

I have RES eating pellets off the surface in the evenings in an area that is shaded by trees and out of direct sunlight.

My pond just got water this month so I don't know if it has snails are not how long does it take to get them? I don't have any grass or veg in the pond ether

Have you already stocked the CNBG & RES?

If you put a limestone rock in shallow water I bet you can tell if you have snails within a week. Algae will grow on the rock, and snails will be attracted to the algae.

I lined my ponds edges with 2-3" limestone crushed rock and the snails seem to love the fresh algae that grows abundantly on the limestone. If I get a rain event that causes the pond to rise a few inches, the area of increased water will have a fresh, bright green band of new algae, and the snails will be concentrated in this fresh band of growth. It also appears to me the RES must eat the snails up as far as is practical for them to get, as the really shallow water maintains more snails. When the water gets cold in the fall, look for the snails on the underside of rocks or leaves.

It is my understanding (but I'm no expert) that RES eat many of the same things that BG or CBG would eat. Insect larvae, minnows, etc. It is just that they also have the capability because of the crusher plates to crush and eat snails and snails happen to be one of their preferred food sources.

But in the absence of snails, I think they will eat other stuff.

Would it be a bad idea to mix a small portion (maybe 10%?) of sinking pellet food in with the floating just for this reason? To feed fish that don't transition to eating surface feed?

I feed some of both. Of course there is no way of telling if the sinking feed is getting cleaned up. In my case though, I'm pretty certain that the limited amount of feed I'm feeding is getting eaten (FHM and CC will clean up any that my BG don't get to first). If I were trying to feed the maximum amount they could eat, I would be more leery of feeding too much sinking.

Here are some links and information on RES that might be helpful.

RES info and links

Stocking them Wednesday Aug 13