[header] How to keep a turtle healthy [title] Provide an enclosure with adequate space. [step] Ten gallons per inch of your turtle is a general rule. 50 gallon (189.3 l) minimum for a baby turtle (younger than a year old) and 120 + for an adult. 
Make sure that you have a general idea of the size your turtle will reach when full grown so you are not blindsided with keeping a turtle you cannot maintain. [substeps] Decide on a land or aquatic turtle.