My 3-year-old red-eared slider has been home for two weeks, kept in shallow water with home heating at about 23 degrees C and no heater. Now it sneezes, has a runny nose, breathes with its mouth open frequently, has white discharge at the mouth corners, and is lethargic.

Severe turtle pneumonia shows side-floating in deep water, mouth-breathing at the surface, audible breathing, blocked nostrils, and refusal of food and water. First isolate the sick turtle, control temperature swings, and keep it steadily around 28 degrees C to boost its body functions.

Take it to a vet for proper treatment. If a hospital is inconvenient, use azithromycin or amoxicillin baths (about 0.5 g per 500 ml water per 500 g turtle), 1-2 times daily for 30-60 minutes, plus oral amoxicillin with vitamins, and supplement vitamin or glucose during care.