Have you ever seen an orange tail molly in Dutch waters? If not, you should go to the ABC Islands. That’s an abbreviation for Aruba, Bonaire, and Curaçao. These islands are located not far off the northern coast of Venezuela. In the small Antillean islands (i.e. the ABC islands) the population of mollies in the sea is small, probably because of the multitude of predators. However, this small population seems to be of utmost importance as it is a very stable one, in contrast to the populations of inland waters, both fresh and super saline (i.e. landlocked saltwater lagoons), which habitats seem to be more attractive than the sea. In the inland waters, however, mass mortalities occur of adverse conditions, both biotic and of abiotic nature. Therefore the inland populations are subjected to occasional extinction, and the habitats have to be repopulated from the sea. This may be the explanation that no genetically fixed differences could be found between populations from freshwater, from the sea and from super saline water. The inland migration after rainfall is not caused by the freshwater itself, but by an organic compound that is found in inland water, whether fresh or saline and also in rainwater after it has been in contact with the soil. So the next time you want to go scuba diving, snorkelling, or bird watching, why not choose the ABC islands? They are friendly, safe, and clean, and you can even drink the tap water! But do not forget to look for the local molly: Poecilia vandepolli.