Ari Daniel Tomato clownfish, like the one seen here nestled in a sea anemone, lose all but one of their white stripes (the head bar) as they grow up. Camille A. Sautereau hide caption In the Disney film Finding Nemo, the clownfish Marlin worries that his son Nemo may have suffered an injury, and asks him to count how many stripes he has. Nemo gets the answer right — three. But in another species, the tomato clownfish, all but one of those stripes disappear as the young fish mature. Now, in a paper published in PLOS Biology, researchers present a set of experiments that appear to explain what triggers the costume change — both environmentally and genetically. They say tomato clownfish, in response to an unpredictable world, appear capable of flexibly adjusting when they lose their stripes based on cues from other fish and their habitat.…