I knew I wanted to write about a species of seahorse today — the question was, which one? There are 54 species of seahorse, which is a lot to choose from. I’ve only written about one before, the pigmy seahorse, which is one of the smallest seahorse species. So today I’m going to go in the opposite direction and write about the biggest seahorse, the pacific seahorse.

The pacific seahorse is also known as the giant seahorse, which is a little bit of a misnomer, since seahorses don’t get all that big. Still, pacific seahorses do get fairly large, reaching 30 cm in length. They range in colour from maroon to yellow and brown-green. These guys also have fun patterns on their bodies, which can take the form of dark and white spots, or streaks. They have the typical seahorse look, with an elongated snout and a curled, prehensile tail.

A lovely closeup of a pacific seahorse looking bashful. Image by Jennifer Dunne, CC BY 2.0, via Wikimedia Commons

The colour of giant seahorses varies in part because this species relies heavily on camouflage. They do not really have any other defence mechanism, since they are reasonably small and are quite poor swimmers. So the seahorses anchor themselves to some or eelgrass or coral and blend in — they can even change colour to better hide themselves.

So where can you find these adorable seahorses? Well, you’ve probably guessed that they live in the Pacific Ocean, but it’s a pretty big ocean so let’s get a little more specific. They reside in the coastal regions of the eastern Pacific, from California to Peru, including the Galapagos islands. They like to hang around reefs, and are generally not found any deeper than twenty meters.

Pacific seahorses feed on a diet of small invertebrates and zooplankton. They detect prey using a literal line system, which can sense changes in water pressure and movements around them. Seahorses also use sight and smell to locate their meals. Unlike real horses, seahorses don’t have teeth, and have to suck up their prey through their snouts.

A pacific seahorse doing a pretty good job of blending in. Image by LASZLO ILYES from Cleveland, Ohio, USA, CC BY 2.0, via Wikimedia Commons

Mating in pacific seahorses begins with males fighting for access to females. This involves head butting and wrestling using their tails. Once a female-male pair is formed, the two engage in a long courtship dance, which starts with the two rubbing their heads together. They then intertwine their tails and anchor on a piece of grass or coral, and proceed to bob up and down at one another. Pacific seahorses take courtship seriously: the two can stay entwined for up to three days.

Once both seahorses are ready, the male will approach the female and display his breeding pouch. The female will then deposit her eggs in the pouch, and leave the male to do the rest of the work. The eggs hatch after fourteen to fifteen days, and are usually released when the moon is full and the tides are high. This is the time when there are the most resources available for the young, which increases their chances of survival. There can be up to 2000 eggs per clutch. That’s a lot of baby seahorses!

Seahorses are some of my favourite fish ever, and not just because they they resemble horses. It’s because they are so strange and silly that it’s hard to believe a creature like that actually evolved. Unfortunately due to habitat loss and overfishing (seahorses are often caught by shrimp fisheries), the population of pacific seahorses is declining. Hopefully that trend doesn’t continue and these funny guys will be around for a while!

Cover image by Robert Scoble, CC BY 2.0, via Wikimedia Commons