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I have two baby Turtles-RES (Red Eared Slider) who are 4 months old, can anyone tell me how much should I feed them and most important how to tame the?

Feeding... pellet amount roughly 1/2 - 2/3 the size of their heads. Taming... they'll adjust to you eventually, especially once they associate you with food.

I use to feed mine 3 times a day. One day 2, another 3

For taming, I think it's good to have practice handling them--that way they get used to being picked up (though they probably won't ever particularly like it), and you get used to picking them up too. There's one YouTube video that helped me with my turtle, who used to wriggle his way out of my hands: https://www.youtube.com/watch?v=RH11WErvbfo

Obviously you'll need to wash your hands thoroughly after to avoid salmonella poisoning, but it might help to handle them early and often so they're better prepared for vet trips, etc.