Yes, baby turtles are fragile and a lot of them die, but that's mostly because of an improper habitat and lack of knowledge. I had 3 hatchlings at one time and all 3 have survived. So it's NOT all doom and gloom. First, what type of habitat do you have them in.. what size tank, basking area, temperatures, water heater, lighting, etc. You may want to consider taking the more active turtle out while you let the other feed in the tank. Many times one of them ends up bullying the other or is a more aggressive feeder and gets all the food before the other has a chance. Another thing is that turtles like privacy and are easily spooked. Try not to hang around their tank for a bit until they get use to you. You could also try putting something around the glass of their tank to prevent them from seeing out and that may make the shy one a bit more comfortable. This is not unusal behavior for new turtles.. just be patient and give him a bit of time to adjust. Please keep us posted on any changes..
