And it's all in their heads, perfectly shaped to sneak up and quickly snatch prey, researchers from the University of Texas at Austin report.
"A seahorse is one the slowest swimming fish that we know of, but it's able to capture prey that swim at incredible speeds for their size," research associate Brad Gemmell said.
The prey are copepods, extremely small crustaceans that are a critical component of the marine food web.
Copepods escape predators when they detect water waves produced in advance of an attack, and they can swim away at speeds of more than 500 body lengths per second, which would be like a 6-foot person swimming under water at 2,000 mph.
The researchers discovered the seahorse's head is shaped to minimize the disturbance of water in front of its mouth before it strikes, creating a "no-wake" zone to keep fluid disturbances from alerting its prey before it strikes.
"Seahorses have the capability to overcome the sensory abilities of one of the most talented escape artists in the aquatic world -- copepods," Gemmell said. "People often don't think of seahorses as amazing predators, but they really are."