If you or someone you know has the luxury of a swimming pool or nearby watering hole, your dog is likely to take an interest, too. Swimming may well be one of the healthiest and most entertaining exercises a canine will ever encounter. But it’s not without its hazards. So responsible parents would do well to take note: not all dogs take gracefully to the water. They and others, like geriatrics and epileptics, need special attention while poolside.