turtles are omnivores, and actually eat very little animals. How big are you talking when you say hatchling? 1" or 2" in size? you can try feeder guppies, they are really small and might entice it to eat, if not itll get to it later.
I have a RES and shes a big girl now but she rarely eats meats or pellets she loves her fruits and veggies.
You can get duckweed and alot of it and throw it in the tank. They can go for a long period of time without eating but I dont think yours has any reserves built up to do that.
That's not a planted tank. That's a jungle with glass around it- MFDROOKIE Circa 2011