Sea horse care sheet

 

Seahorses are a fish belonging to the family Syngnathidae, which also includes pipefish and leafy sea dragons. There are over 32 species of seahorse, mainly found in shallow tropical and temperate waters throughout the world. Seahorses are so named for their equine appearance. Although they are fish, they do not have scales, rather a thin skin stretched over a series of bony plates arranged in rings throughout their body. Each species has a distinct number of rings. Seahorses swim upright, another characteristic that is not generally shared by their fish relatives who swim horizontally.

 

 

New Zealand Pot Bellied Seahorse

Hippocampus abdominalis

 

Description

The N.Z. native seahorse (Hippocampus abdominalis) or Pot-belly seahorse is one of the largest seahorses, growing up to 35 cm in length. Seahorses are despite their looks a fish that swims in an erect position, the head is held at right angles to the body, the eyes can move independently of each other, and the tail is prehensile to enable them to hang on to objects. Instead of having scales, as most other fish, seahorses have a layer of skin stretched over bony plates that are visible as rings passing around the trunk. The dorsal fin propels them forward and they steer using the pectoral fins on either side of the head. As the common name suggests, this species has a large stomach. In common their bodies are well camouflaged with colours in individuals ranging from brown, yellow, grey, white, orange or mottled, with dark spots and blotches on the head and body. Males differ from females in that they have a brood pouch, longer tails, and a shorter snout. The potbelly seahorse can live to 10 years in the wild and breed three times a year.

 

Range

The Pot bellied seahorse is found in the south-west Pacific around New Zealand and Australia. In New Zealand, it is found around both North and South Islands and in Australia from Newcastle, New South Wales then on the southern coast to Tasmania and South Australia.

 

Habitat

Usually found inhabiting harbours and sheltered coastlines amongst seaweeds around rocky areas in fairly shallow water, can be found in deeper waters as well. They are more active at dusk and night than in the daytime spending most of the day anchored by their tail to rocks or weed.

 

Diet:

Seahorses feed on crustaceans, such as amphipods and shrimp, which are sucked into their tube-like snouts and ingested whole, in the aquarium they can be fed on live 

Shrimp, mosquito wrigglers, daphnia, guppy fry and whiteworms (very fatty) also frozen foods such as mysid and brineshrimp

 

 

Breeding

In seahorses it is the male and not the female who becomes pregnant. At 6 months old males develop a brood pouch on the belly, but males don’t breed until they are about a year old. Breeding takes place in spring and summer; after a two day courtship the male opens the top of his pouch the female inserts her ovipositor and lays her eggs. Fertilisation then takes place and they are embedded into the wall of the pouch, the pouch is similar to the womb of mammals and contains placental fluid. This fluid is used to remove wastes and supply nutrients and oxygen to the developing eggs, as it gets closer to the birth the fluid changes to match the surrounding seawater salinity so the shock isn’t too much for the fry at birth. Males go into labour at around 30 to 35 days of gestation, and up to 900 fry can be produced that are miniature versions of the adults, the fry are fully independent after birth and fend for themselves.  They spend the first week or two clinging to flotsam on the surface and as they get bigger they sink to the bottom.

 

Keeping in Aquaria

Seahorses should only be kept in a mature, cycled saltwater aquarium. A seahorse tank must have gentle to moderate currents for them as they are not strong swimmers and to enable them to be able to feed properly. There must be adequate biological filtration and you should do water changes of 5-20 percent per week. Water should follow these guidelines before you introduce a seahorse:

pH - 8.0 to 8.3 

Specific gravity - 1.021 to 1.024 

Ammonia - 0 

Nitrite - 0 

Nitrate - <20 ppm

Temperature – Hippocampus abdominalis (9 to 18C), H. kuda (………)

 

Seahorses should be kept in a species only aquarium or with compatible tank-mates such as pipefish or fish from the goby family. Seahorses are slow feeders, and in an aquarium with fast, aggressive feeders, the seahorses will be edged out in the competition for food. Special care should be given to ensure that all individuals obtain enough food at feeding times. Seahorses can co-exist with many species of shrimp and other bottom-feeding creatures. 

Although seahorses can be kept in smaller aquariums the larger the tank the easier it is to keep the water parameters stable. Height in the tank is important to allow natural behaviour in courting and mating, a depth of 2 to 2 ½ times the length of the seahorse is needed for this.

Hippocampus abdominalis need cooler temperatures to remain healthy and during the warmer months it will be necessary to have a Chiller on your system, prolonged warmer temps can lead to fungal and other problems that will be fatal to them.