This tour will allow you to encounter whale sharks the largest fish on the planet they can grow up to 15 meters in length the whale sharks prefer warm water surface in those areas where there are outbreaks of colder rich nutrient water these conditions favor the growth of plankton on which they feed this is one reason why there are so many whale sharks in the waters between holbox and isla mujeres in summer they are often seen with schools of jacks and stingrays