Eastern spotted newt eft setup
 

I recently set up a newt tank. Its a 55 gallon aquarium. I have the water down about 4 inches and have a floating turtle dock which I purchased from a pet store. I have live and fake plants, some guppies and ghost shrimp. The newts I bought are about 2 to 3 inches, and still red. I was hoping for them to be green phase. Some are darker color and look like they are starting to change. Anyway, will this set-up be ok? Can red efts swim back up to the floating dock? Can they even swim? Thank you for any input.

A terrestrial set up with a small water dish would be better. They will drown in that big tank with that much water.

I lowered the water about 8 inches in the 55g. Newts are on floating hyacinth and a floating dock. I saw them swim down to bottom and make it back up to platform fine.
What do you think about feeding? I chopped up earthworms and put them in a separate container for 3 hours. Some of the worms were gone so they did eat. How often should I feed?

Like Michael said, they are terrestrial at this stage. While they may indeed survive in an aquatic set-up, they also may not. It is less than ideal, at best. This species is known for being delicate enough, as is.
If they were mine, I would set them up in a planted vivarium with lots of hiding places. Mist them regularly, and feed them chopped earthworms, isopods, fruit flies, pinhead crickets, etc. Feed them three or four times a week- let their body weight be your guide. If they are skinny, feed them more. If they are fat and not eating everything you put in, feed them less.

Thank you for the information guys. I will try it out.