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Home › Sea Life › Marine Species › Vertebrate › Seahorses › Pygmy Seahorse

Interesting Facts about Pygmy Seahorses

[Seahorse Phylum: Chordata] [Class: Actinopterygii] [Order: Syngnathiformes] [Genus: Hippocampus]

Pygmy seahorses (Syngnathidae) are tiny vertebrates (less than one inch long) and most common throughout the Coral Triangle in Southeast Asia.

This section contains fun facts about pygmy seahorses, including where they're found, what they eat, and why the reproductive strategies of the seahorse family Syngnathidae are so unique.

Where Do You Find the Smallest Seahorse?

The largest pygmy seahorse species, the Bargibant's pygmy seahorse, is less than three (3) centimetres long (0.94 inches).

They have a perfect match with the colour and texture of host corals.

So, you're going to need some expert tips for spotting them (between 15 and 40 metres deep).

• Annella spp. and other types of sea fans (look for Hippocampus denise)
• Muricella spp. gorgonians (look for Hippocampus bargibanti)
• Algae and soft coral rubble (look for H. colemani and H. japapigu)

Pro Tip: Having a keen-eyed dive guide is great for divers who enjoy macro photography. However, always avoid touching marine life and shining strong lights directly into their eyes - pygmy seahorses are timid animals that are easily stressed.

Pygmy Seahorse Habitat

There are some common and reliable places to find most of the pygmy seahorse species around the world. Here's a few of the top regions.

Australia

Head over to some of the known sites on the Great Barrier Reef, such as Ribbon Reefs and Osprey Reef, and you should see Bargibant's seahorse and the yellow pygmy seahorse.

Venture a little further to the Tasman Sea and you have a good chance of spotting Hippocampus colemani at Lord Howe Island.

Indonesia

One of the best-known hotspots for scuba diving in Indonesia is Raja Ampat. Sightings of Denise's pygmy seahorse and Hippocampus bargibanti are common here.

Other superb sites for all kinds of macroorganisms include Komodo National Park, Lembeh Strait (North Sulawesi), and Wakatobi.

Solomon Islands

Pygmy seahorses are frequently found in the Solomon Islands, especially on several types of sea fans (Gorgonia) at depths ranging between 15 and 40 metres.

The Philippines

There's no shortage of top dive sites in the Philippines, including Apo Reef, Anilao, and Tubbataha Reef. Plus, the pygmies at Dauin (Negros Island) create great subjects for macro photographers.

Pygmy Seahorse Characteristics

Pygmy seahorses are tiny and fascinating. They are masters of camouflage and disguise primarily living around the algae-covered reefs in the tropical Indo-Pacific.

They're usually found anchored to specific coral species or sea fans (gorgonians) that perfectly mimic their colour and texture perfectly.

Despite their miniature size, some special pygmy seahorse adaptations have helped them evolve and survive some significant threats to their long term existence.

Camouflage and Colouration

There are few marine vertebrates that can outshine miniature seahorses as camouflage specialists. The colour and texture of their skin (often including warty bumps or tubercles) exactly match those of their host.

In fact, some species of pygmy seahorses can change the colour to better blend in with their surroundings as and when needed.

For example:

• Hippocampus bargibanti are pink or yellow with matching tubercles.
• Hippocampus denise have a smoother body with yellow and pale orange skin colour to match their host corals.
• Hippocampus colemani are mostly white with some dark spots, ideal for life among Halimeda algae and rubble.

Anatomy and Behaviour

Some of the key features used to identify the pygmies differ little from those seen in the larger types of seahorses (order Syngnathiformes).

For example, seahorses do not have eyelids so they sleep with their eyes open. Even so, the eyes are able to move independently of each other.

Instead of fish scales, the skin is covered with bony plates fused together to form a tough exoskeleton. They also have a distinct bump on the head (called a coronet), although it varies by species.

But wait - there's more:

They're one of the most sedentary fishes in the ocean, often spending their entire life cycle on a solitary coral fan.

Even so, it's common to see monogamous pairs occupying the same coral branch. They use their prehensile curled tails to anchor themselves and use their toothless snout to feed on tiny planktonic crustaceans.

Pygmy Seahorse Size

Satomi's Pygmy Seahorse (Hippocampus satomiae) is the smallest seahorse in the world, growing to thirteen (13) millimetres long (half of one inch).

Fully mature Hippocampus bargibanti can grow to 2.7 centimetres long (0.94 inches), but they still rank with the smallest seahorse species.

Interesting Fact: Even though the pygmy seahorse scientific name is Hippocampus, the common name seahorse comes from a striking resemblance to its 'equine' namesake.

What Do Pygmy Seahorses Eat?

There is a valid reason why they're known as 'deadly killer seahorses' - and it's not pleasant. These tiny, stealthy carnivorous predators feed mostly on microscopic drifting animals that are barely noticeable in the water column, including:

• Amphipod larvae
• Bryozoa
• Copepods
• Mysid shrimp larvae
• Zooplankton (rotifers)

Fun Fact: In 1969, the pygmy seahorse Hippocampus bargibanti was the very first pygmy species discovered by scientists while they were examining a gorgonian fan coral in a laboratory. The rest of the species have only been discovered since the year 2000.

Types of Pygmy Seahorse Species

How Do Pygmy Seahorses Reproduce?

The pygmy seahorse lifespan rarely exceeds two (2) years in the wild, and even less when they are kept as pets in home aquariums.

They are monogamous and stay with a chosen companion for life. Male seahorses have a brooding pouch located at the front of the tail.

Here's the thing:

It's the male seahorse that nurtures the fertilised eggs for a period of several weeks until the microscopic young seahorses appear.

The male is relinquished from his parental duties, and often begins to mate again for further breeding activities, within a few hours. And so, the seahorse reproductive cycle begins once more.

Pygmy Seahorse Predators

Despite being masters of camouflage, pygmy seahorses and not invisible. They still face multiple predators in the wild, and some increasing threats due to human-related activities, including:

• Small reef fish, especially butterflyfish, damselfish, and wrasses consume small invertebrates that live on coral fans. Hence, they will eat a pygmy if it moves.
• Some marine crustaceans, such as crabs and shrimp, often live on the same type of coral formation as pygmies. They often prey on juvenile pygmy seahorses.
• It's not uncommon for small cuttlefish and octopuses to take advantage of pygmy seahorses if they're spotted and within easy reach.

Human-Related Threats

• The direct effects of coral bleaching, pollution in the ocean, and sedimentation are destroying the habitats of obligate coral dwellers (especially those living on gorgonian sea fans).
• Rising sea temperatures, often called climate change, causes tremendous stress to corals. In turn, they become more vulnerable to coral diseases and death (due to weakened coral skeletons).
• Pygmy seahorses tend to be too small to be directly targeted by fishing. However, they are sometimes caught unintentionally in fine-mesh nets or coral collection operations.

Pressure from Scuba Diving and Photography

There have been some recorded instances where 'untrained' divers have touched or moved sea fans when taking photographs underwater. Doing so can harm the coral as well as the tiny seahorse.

Using strong torch lights and strobes can also stress small marine life. Remember, seahorses have no eyelids and they rely on remaining still for their personal safety.

Important: The IUCN Red List assessed some of the pygmy seahorse species as being widespread and of "Least Concern" (LC). But, in 2023 they listed the Sodwana pygmy seahorse (Hippocampus nalu) as "Near Threatened" with a "Decreasing" population trend.

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