I started candy critters about a month ago. I know which ones I need, however Nothing is showing up. I've tried taking out my mushroom and I get mice. If I use a regular mushy, I get the mice and dragons

Are you using the right food, for the type which that setup is correct for?

yes, berries for candydevil. I was getting them before, now not sure why they are not visiting

Can you advertise for them ? That would indicate if you are actually set up correctly x

Check again in your list if you have the correct shapes and colors for your setup.
It looks like you have attracted violet candydevils before, so you hopefully stored the list to know which candies you need at each position.

I know what I need to attract, (correct shape, correct color) but NOTHING is visiting in the way of candy critters

Using advertising only works for rainbow candies - Mike made the exception for candies to be advertised so a short cut for testing shapes and colours couldn’t be used.  Definitely with the results on the plates either wrong shapes or colours or wrong positions - maybe first try changing the positions and see if anything than pops us.

I know the green triangle goes in the left spot. Shouldn't I be getting the orange candy devil show up?NOTHING is showing up, just the wrc

Your results really suggest things may be in the wrong positions - again would suggest shuffling the shapes around to confirm.  While sometimes different colours can be stubborn to turn up if the triangle was in the correct position yes, I would expect that you would have had a devil turn up on the plates by now.  Hence I would be giving a shot at a different position - it isn’t going to cost anything except a bit of time to retest the positions.