They will injure or be injured by the crab and will eat the ADF. They need a basking dock or platform with a heat lamp. They need food such as mealworms, butterworms, frozen bloodworms, turtle pellets and aquatic vegetation. They may eat aquarium gravel, so large pebbles or sand is best. They will need at least a 55 gallon tank very soon. VERY strong filtration is required. Good luck! Turtles are very rewarding, but require a lot of care- if properly cared for, youre looking at about a 30 year commitment.