Breeding seahorses

Dear Brian:

No, sir — as a beginner, you needn’t be concerned that your seahorses are going to overpopulate your aquariums when they begin breeding so that you are overrun with juvenile seahorses. Allow me to explain it a little more detail.

Although seahorses often produce large broods of young, there are a number of reasons why you needn’t worry that you are going to be overrun with homegrown Hippocampus, sir.

Large seahorses such as Mustangs and Sunbursts (Hippocampus erectus) can and do produce large broods of babies when they are actively breeding. Large males that are experienced breeders typically produce anywhere between 100-800 offspring after mating, but virgin males and inexperienced breeders often produce much smaller broods. For instance, if you order male/female pairs of Mustangs or Sunbursts from Ocean Rider (seahorse.com), you will be receiving young adults that have recently reached sexual maturity. As such, the number of fry they produce when breeding at this young age typically numbers in the dozens, rather in the hundreds.

Moreover, Brian, rearing the newborns and keeping up with their endless appetites is always a daunting challenge for the home hobbyist, so that only a very small proportion of the baby seahorses are apt to survive in the long run.

There is a always a steep learning curve when it comes to rearing newborn seahorses, sir, and it’s quite common — perhaps even the rule — for the home breeder to lose the entire brood during his or her first few attempts at rearing. But as you refine your methods and become more proficient at providing suitable live foods for the newborns and work out the feeding regimen that’s most efficient for your particular circumstances, your results will get better. You will have more of the fry surviving for longer periods, until eventually you are able to raise a few of the fry from a few of the broods to maturity. That is a realistic goal for any home hobbyist working with Mustangs and Sunbursts who is willing to put in the necessary time and effort, which can be accomplished using a basic nursery tank and a staple diet of newly hatched brine shrimp.

Secondly, you shouldn’t automatically assume that a mated pair of seahorses are going to immediately begin breeding once they have been successfully acclimated to your seahorse tank. The conditions in your home aquarium are no doubt much different than conditions the seahorses are accustomed to at the aquaculture facility. At Ocean Rider, the seahorses enjoy an open system featuring pristine water quality, natural ocean water and natural sunlight, and thrive in huge holding tanks with lots of room to roam. That means that your first pair of seahorses will be adjusting to a small, closed-system aquarium with artificial saltwater and artificial lighting. As a result, many times seahorses don’t immediately set up housekeeping and begin breeding in a home hobby tank. It may be many months or years before a given pair settle down and produce their first brood, particularly if you receive your seahorses when the breeding season is long past for Hippocampus erectus in the wild.

As you know, breeding in Hippocampus is often seasonal, regulated by cyclical changes in water temperature, day length, and salinity (monsoons). In the wild, both temperate and tropical seahorses breed best during the summer months and typically take a break from breeding during the offseason. For example, the breeding season for our native American H. erectus begins in April and lasts until the seahorses move into deep water with the onset of winter. Although domesticated seahorses that have been born and bred for aquarium life for generation after generation are no longer as strongly dependent on such environmental cues and will often breed year-round in captivity, even captive-bred seahorses sometimes experience a lull in the festivities at this time of year. That’s just their natural breeding cycle, the rhythm of life built into their genes.

So if you are concerned about a population explosion of seahorses eating you out of house and home, Brian, or you just don’t feel you are up to the challenge of raising baby seahorses at this point, it is relatively easy to prevent Mustangs and Sunbursts (H. erectus) from breeding by manipulating these environmental cues. If you don’t want your new seahorses to breed, just gradually reduce the water temperature to around 72°F and leave the aquarium light on for no more than 10 hours each day. In that case, the relatively cool water temperature and the reduced hours of daylight will affect the hormonal levels of the seahorses and they will cease actively breeding, just as they do in the off-season.

If you want your seahorses to breed again, just gradually raise the water temperature (no more than 2°F daily) to around 77°F, and keep the aquarium light on for a least 12 hours each day, and the seahorses will respond to the increasing water temperature and day length with a renewed interest in courtship and breeding.

So worrying about what to do if your first pair of seahorses produces a brood of babies before you feel you are ready to tackle rearing the young need not be your overriding concern at this time, Brian. You can easily turn off the breeding behavior in your seahorses if you wish, and even if they do begin breeding regularly, the challenges involved in raising the young mean that it is extremely unlikely that you will ever face a situation where you are raising more seahorses then you can accommodate.

If you’re interested in breeding and raising seahorses, Brian, then I would recommend that you participate in the Ocean Rider training program for new seahorse keepers in order to maximize your chances of success. It is completely free of charge and will teach you everything you need to know about the care and keeping of domesticated seahorses. For example, the training course includes lessons entirely to courtship and breeding and to rearing the young, and also provides detailed discussions of successful rearing protocols that have been developed for Hippocampus erectus by professional aquaculturists.

The training program is a correspondence course that is conducted entirely via e-mail, sir, and if you would like to give it a try just contact me off list ([email protected]) with a brief e-mail that includes your full name (first and last) and I will enroll you in the training program and get you started off the first lesson right of way.

Best wishes with all your fishes, Brian!

Happy Trails!
Pete Giwojna