My turtle of over ten years recently stopped eating and stays in the corner; could new sick turtles have infected it?

There are many reasons a turtle stops eating. First, turtles are timid and may have been stressed by the two new hatchlings, and stress makes appetite drop; the fix is a safe, comfortable environment with proper water temperature, minimal disturbance, and fresh food to slowly regain appetite.

It may also be disease such as pneumonia, shell rot or gastrointestinal illness that removes appetite. Signs of sickness include lethargy, refusal to eat or drink, floating, mouth-breathing and loose stools. Without a clear cause, appetite is hard to restore; try a marketed appetite-recovery bath, and if no improvement, take the turtle to the vet for diagnosis and treatment.