I don't think there's much chance of identifying one of these fishes from a photo. There are about 300 species in the Syngnathidae. Allowing for all the seahorses, seadragons, pipehorses and distinctively coloured pipefishes, I guess that there may be at least 150 species of varying sizes from various habitats around the world which look more or less like this. They can be distinguished by fin-ray counts, mouth proportions and, in particular, by the structure of the male's brood pouch. But I doubt if anyone could even make an educated guess from a photo.
