Short Answer
The hippocampus is the seahorse emblem stamped into the caseback of Omega Seamaster watches, and it has been part of that line since 1956. When buyers search for a "replica hippocampus 2015," they mean a copy of a Seamaster built around 2015 references, most often the Seamaster 300 Master Co-Axial, the Aqua Terra 150M, or the Planet Ocean 600M. The hippocampus is not a model name. It is a caseback detail, and it is one of the fastest ways to separate a genuine Seamaster from a copy.
What the Emblem Shows
On genuine Seamaster casebacks the seahorse is drawn in deep relief with a clear tail curl, defined ribs, and a short snout. Text around it lists the model name, the water resistance rating, and the reference number in a clean ring. Omega stamps these details, so the edges stay crisp under magnification and the surrounding metal keeps a uniform brushed finish. Copies tend to soften the tail, merge the ribs into one shape, or cut the lettering at uneven depths.
2015 Seamaster Families That Carry It
- Seamaster 300 Master Co-Axial, 41 mm, steel and titanium cases
- Aqua Terra 150M Master Co-Axial, 38.5 mm and 41 mm cases
- Planet Ocean 600M Master Co-Axial, 42 mm and 45.5 mm cases
- Diver 300M, including ceramic dial versions sold that year
How to Inspect a 2015 Hippocampus Caseback
You need a 10x loupe, a soft cloth, and a light you can angle from the side. Work through these steps in order.
- Lay the watch face down on the cloth and aim the light across the caseback at a low angle so the relief casts shadow.
- Count the ribs on the seahorse tail and confirm each rib is a separate, sharp line.
- Trace the ring of text with the loupe and check that every letter has a straight edge and even depth.
- Match the water resistance number to the model it claims to be, 150M, 300M, or 600M.
- Check the reference number against the case size, dial color, and bracelet that came with the watch.
- Weigh the watch on a kitchen scale and compare it with the published weight for that reference.
- Look at the caseback threads and gasket seat, which should sit flush with no machining burrs.
Movement and Case Checks That Go With It
A correct caseback does not prove the rest of the watch. On 2015 Master Co-Axial references, the rotor turns with a smooth sweep and the seconds hand glides at 25,200 vibrations per hour on most models. Copies often tick in visible jumps. Check the crown action as well. A genuine Seamaster crown threads in with light resistance and no grinding, and the helium escape valve on the Planet Ocean sits flush with the case flank.
Legal Note
Selling or importing counterfeit watches is illegal in the United States. U.S. Customs and Border Protection can seize shipments of counterfeit goods, and trademark owners can pursue civil claims against sellers. Buy from an authorized dealer or a seller who provides a documented service history if you want a genuine hippocampus caseback.