Zootierliste suggests the longsnout or the long-snouted seahorse* (H.reidi or H. guttulatus). To be honest, I rarely believe published identities of sea horses, except for the easiest species (such as pot-bellies and barbs). Luckily you can download a very official and detailed key from ID guide | iSeahorse - but it isn't easy to use with photos of specimens, unless you have plenty of detailed close-ups.
