🐠 Big-Bellied Seahorse (Hippocampus abdominalis)
One of the World's Largest Seahorse Species, Reaching 30-35cm • A True Cold-Water Species Needing a Dedicated Chiller • For Expert Keepers With Prior Seahorse Experience
 
📋 This species is a temperate, cold-water seahorse native to Australia and New Zealand, and needs cooler water than a typical tropical marine setup, we recommend 18-24°C, which will mean a dedicated aquarium chiller rather than standard tropical heating. This is also a difficult to expert-level species, requiring frequent feeding sessions of live or enriched frozen mysid shrimp, several times daily, and its needs can become unpredictable if not met precisely. We recommend this species only to keepers with real prior seahorse-keeping experience and a dedicated cold-water setup already in place.
The Big-Bellied Seahorse, also known as the Pot-Bellied Seahorse, is one of the largest seahorse species in the world, reaching lengths of up to 30-35cm, dramatically larger than most seahorses kept in the hobby. Males display a prominent, rounded white brood pouch, while females have a more slender profile, and coloration varies widely between individuals, from yellow and tan to brown, grey, and olive green, often with dark mottled spotting.
It comes from the cooler coastal waters of Australia and New Zealand, inhabiting rocky reefs and seagrass beds at depths down to 104 metres. Every Big-Bellied Seahorse we ship is feeding well.
An interesting fact: unlike most seahorses, which typically form monogamous pairs, this species doesn't consistently pair up in the same way. It's also a strong swimmer compared to most of its relatives, capable of covering longer distances rather than relying solely on its prehensile tail to anchor in place. Like all seahorses, males carry fertilized eggs in a specialised brood pouch, incubating them for around four weeks before a nighttime hatching, often timed to coincide with the full moon. This species has no teeth and no stomach, feeding by suction through its tube-like snout, which is why frequent small feedings matter so much. It's reef safe with caution, and should never be housed with corals or anemones that have stinging tentacles. It reaches up to 35cm, so a 208L tank at minimum, taller rather than wider, suits it well.
 
💡 Highlights
🐴 One of the World's Largest Seahorses: Reaching up to 30-35cm
❄️ A True Cold-Water Species: Needs 18-24°C, typically requiring a dedicated chiller
🧠 Expert Only: Best suited to keepers with real prior seahorse experience
🍽️ Frequent Feeding Essential: No stomach, so small, frequent meals matter
⚠️ Reef Safe With Caution: Never house with corals or anemones with stinging tentacles