Almost all the wildly varied, colorful fish that populate coral reefs start life as tiny, colorless, tadpole-like larvae. Telling one from the other is nearly impossible – even for experts – and this presents a difficult challenge to those who study the ecology of the reefs. Prof. Rotem Sorek of the Weizmann Institute of Science; Prof. Roi Holzman of the School of Zoology and The Steinhardt Museum of Natural History, Tel Aviv University; and Dr Moshe Kiflawi of Ben Gurion University have now produced a way to understand precisely which species of larvae are present in the water around reefs. Their study, which involved genetic “barcoding” of nearly all the fish species in the gulf between Eilat and Aqaba, not only showed which larvae were in the gulf, but how many of each were swimming around, at what time of year and at what depths. This study was recently published in the journal Nature Ecology and Evolution.