It is not easy to find seahorses on the Greek coast. However, in a small gulf of the Chalkidiki peninsula, Vasilis Mentogiannis found many of them in 2007.
The discovery shocked the diver because it was not a favourable habitat for seahorses, lacking sufficient hiding spots from predators.
From that moment on, and with the help of scientists and other divers, he began to create an artificial habitat in the area, placing ropes and false plants to give them shelter.
In recent years, the seahorse population has grown notably.
"It's clear that something must be done to protect them. We are talking about a very small region. Keeping fishing boats off their space is something we could do," says Mentogiannis.
Mentogiannis has encouraged a group of scientists to visit the area this winter to conduct further studies.
But meanwhile, only the divers enjoy nature's spectacle.
"It's a unique phenomenon," says diver Kostas Katsioulis. "The people who dive with us are always very excited after seeing the seahorses: diving allows a very unique approach and feeling."