Big-bellied Seahorse

Big-bellied Seahorse

A coastal seahorse that inhabits intertidal pools, large seaweeds, rocky outcrops, and artificial structures in SE Australia and all around New Zealand.

Zoo Diet

At Living Coasts the big-bellied seahorses are fed 5 times a day. This is usually live brine shrimp (sea monkeys) or frozen mysis.

Wild Diet

Mostly feed on crustaceans and small fish fry or invertebrates. They can expand their snouts if the food is bigger than their mouth, but they cannot chew the food. These seahorses may feed up to 30-40 times a day, as they don’t have a very efficient digestive system.


Seahorses can be found on their own, in pairs and sometimes in groups. When they are not swimming they will coil their prehensile tail around any suitable growth such as seaweed and wait for planktonic animals to drift by. They suck them up with their small mouth set at the tip of the snout much like a vacuum cleaner.


Females have a territory of about 100 square metres and males have a territory of about 0.5 square metres. Their territories overlap. It’s the males that become pregnant. The breeding pair will put their bellies together and the female will transfer eggs to the male. He fertilises them with his sperm and then looks after the developing young for about three weeks. He then gives birth by contracting his pouch. They can give birth to hundreds of live young, each one independent from birth. 


Hippocampus abdominalis is threatened by localized habitat loss and degradation due to coastal development and by being caught as bycatch in demersal trawl fisheries. Bycatch levels are thought to be low.


Globally, all seahorses are listed on Appendix II of CITES. In Australia seahorses have been subject to the export controls of the Commonwealth Wildlife Protection (Regulation of Exports and Imports) Act 1982 since 1 January 1998 (Lourie et al. 2004). In New Zealand seahorses cannot be targeted by commercial fisheries, but can be sold to Licensed Fish Receivers as regulated quantities of bycatch.

This species occurs in several marine protected areas, including Jervis Bay Marine Park.

We currently do not have any conservation projects ongoing for this species of seahorse. We have in the past worked with the Community Seagrass Initiative in relation to native seahorses (see short snouted seahorse). 

Big-bellied Seahorse Big-bellied Seahorse


  • Latin Name: Hippocampus abdominalis
  • Order: Syngnathiformes
  • Family: Syngnathidae
  • Conservation Status: Least Concern
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