how old does a red ear slider need to be in order to eat guppies ?

Answer 1

As long as the guppy is small enough for the turtle to eat it in one bite, it is OK.

However, fish are not a big part of a turtle's diet- sure, they eat them when they can catch them, but that does not always work. Also try worms, insects, shrimp, krill, etc.

http://www.austinsturtlepage.com

Answer 2

hey guppies aren't supposed to be eaten get feeder goldfish thy more feeling to the turtle