If your turtle has stopped eating all of a sudden, then it should raise some concerns. Though turtles can go without food for long periods and minor changes in appetite and food preferences are normal, it's not normal for a turtle to suddenly stop eating and refuse all food. If this happens, there are a few things you can try at home to try to get them eating again.
Check the temperature and lighting in your turtle's environment:
Since turtles are reptiles, they need an external heat source to keep their metabolism running efficiently. When your turtle is too cold, it will not only eat less, but become less active. Turtles should be provided a heat source either through a reptile light or a reptile-safe heating element. Keep the environment at around 71 to 86 degrees. Make sure the turtle has a cool area to escape to if needed. You should also provide a source of ultra-violet light for at least 10 to 12 hours a day.
Your turtle may be stressed:
If you've just acquired your turtle, or moved him to a new area, then it's possible that he is not eating because of stress. This is especially true if you took your turtle from the wild or moved him indoors from an outdoor pond. Your turtle's appetite will be off for a little while, but may normalize after he becomes accustomed to the changes.
Your turtle may not like the food:
Some turtles are picky eaters and their food preferences can change over time. If the turtle is new to you, do some research as to what type of diet his species needs. Some turtles are more carnivorous than others and will respond to live food such as worms and crickets. Others may prefer berries or certain kinds of lettuces. Try a wide variety of appropriate food.
Check for parasites:
Turtles are susceptible to a wide range of parasites that can affect their intestinal tract and cause them to stop eating. Most parasites cause little problem until their numbers get too high. High-sugar diets, overcrowding, excess heat and poor sanitary conditions can cause parasites to become troublesome and possibly cause death. If you suspect your turtle may be overrun with parasites, contact your veterinarian for treatment.
Fluctuations in your turtle's appetite are normal, but long periods of not eating is cause for concern. Be aware that turtles have slower metabolisms than mammals and can go for quite a while without eating. Some species of turtles stop eating when they hibernate, but a turtle kept in warm, stable conditions should not be hibernating. Any time you suspect your turtle is having a problem, contact an exotic animal hospital, such as TLC First Animal Hospital, for a physical.