Dylan Moore, of Balclutha Primary School, asks :-

How do seahorses swim and how big do they get?

Chris Woods, a marine biologist with the National Institute of Water and the Atmosphere, and who has raised seahorses in aquariums, responded.

Seahorses are bony fishes whose closest relatives are the equally bizarre pipefishes and seadragons. There are around 35 identified species of seahorses but only one in New Zealand, the big-bellied seahorse, Hippocampus abdominalis.

Seahorses have fewer fins than most fishes; they have a large dorsal fin on their back provides their main propulsion, and small ear-like pectoral fins on either side of their heads which they use to steer with.

Seahorses are around 1.5 cm long when first born, but can reach 30 to 35 cm in total length when fully grown. However, just like us humans seahorses do end up being a range of sizes when fully grown! Our species is the largest in the world.

Nobody knows for certain how long seahorses live for in the wild as studies on this have not been conducted yet. Based on seahorses kept in aquariums we know that large seahorses can grow to be more than 10 years old.

In seahorses it is the males who carry and protect the developing babies. Female seahorses deposit their eggs into the male's brood pouch and he then cares for them for about 30 days. The babies are released from the male's pouch and fend for themselves, feeding on tiny zooplankton organisms around them.

The average number of babies produced per male seahorse is 200-300. Bigger males have bigger brood pouches, and so can carry more babies. In large males, broods of more than 700 babies have been recorded.