Salema porgy, a kind of sea bream, or sarpa salpa (in Greek, it can also be a σάρπα) with distinct yellow stripes.
It's fairly common in Greek coastal waters and is also known as the 'dream fish' for its reputed hallucinogenic properties, said to have been appreciated by the ancient Romans. So we were all excited when staying on Corfu, when our son-in-law caught one (the fish in the picture) and we ate it. It was tasty, but no one had any untoward dreams.
Image by Dana Facaros