Identifying this animal is going to be very hit-and-miss. From what I've seen, it's a Corythoichthys species, but which one is hard to say as several species are very similar.
And in Rudie Kuiter's 2003 book "Seahorses, Pipefishes and their Relatives" he shows photos for at least 12 new undescribed species of Corythoichthys.
And there's a rare white form of Festucalex cinctus that looks very similar too.
