Reply To: Male Seahorses Dying

Dear Russell:

I’m very sorry to hear about the problems your male seahorses have been having, sir. Please accept all my condolences on your losses.

I know only too well how traumatic it can be to lose a seahorse that has become a special pet, Russell. As you know, they are much more personable and interactive than other fish, and we hobbyists invariably become quite attached to our ponies.

Believe me, it’s easy for an old seahorse keeper like myself to understand the irresistible appeal of these enchanting creatures. Some hobbyists are simply fascinated by the outlandish appearance, complex behaviors, and surprising habits of these amazing animals. They get a kick out of having a pet that’s truly a marvel of nature, an anatomical oddity to top them all. These are the aquarists that are bored by average, everyday, run-of-the-mill specimens that are pet-store staples. They’re always on the lookout for something new and different, something extraordinary. When it comes to fishkeeping, they favor the oddballs over the ordinary, and the elevated curiosity quotient of these marine marvels is what attracts them about seahorses. There’s a little of that childlike wonder in all of us. Heck, what red-blooded American kid wouldn’t give his two front teeth to keep such curious critters for pets?

Others are attracted by the legendary status of the seahorse. They’re captivated by the chance to keep a fabled beast of mythical proportions that seems more like something out of a fairy tale or a Disney movie than a real, flesh-and-blood animal. For them, a seahorse tank is the next best thing to having a genuine unicorn or keeping winged Pegasus himself in their living room. There’s still a little of the enchanted kingdom in every seahorse keeper, too. Everyone would like to believe in magic, and Hippocampus is living proof that some fairy stories do come true.

Many aquarists are excited by the challenge of breeding and rearing these legendary livebearers. Seahorses are easy to sex, they pair up and mate in captivity readily, and their fry are relatively easy to raise compared to other marine fishes. There is nothing more rewarding than a tankful of healthy, homegrown Hippocampus and many hobbyists feel that seahorse husbandry is the key to assuring their ongoing survival. The prospect of culturing these captivating creatures is thus the clincher for many enterprising individuals.

And a lot of seahorse lovers find it especially satisfying to keep a fish that can become a true pet. Seahorses are real personality fish and many of them actually enjoy being handled. Unlike most other fish that back off when you approach the aquarium and flee in terror if you place your hand in the tank, seahorses soon learn to recognize their keeper and will come out to meet you. They quickly learn to take food from your fingers, and having your pet ponies literally eating out your hand is a very rewarding experience. When one of these shy, enchanting creatures — whose very survival in the wild depends on concealing itself from predators at all times — comes trustingly up to the surface to eat right out of your palm, it’s a thrill you won’t soon forget. The training sessions and daily feedings required for this tend to forge a close, personal relationship between the aquarist and his charges, and hand-fed seahorses often become special pets. Many times they will even include you in their daily greeting, flashing their recognition colors and parading back and forth and at the front of the tank, performing their dancelike displays for your benefit.

So when you lose a seahorse to an illness or injury, it has more of an impact and is harder to accept than the passing of most wet pets. It’s not at all like that dimestore goldfish that you can unceremoniously flush without a second thought when it goes belly up…

But I promise you the same things that make the loss of a pet seahorse so devastating are the very things that make them so rewarding to keep in the first place, which makes it all worthwhile for me in the long run.

And you are quite correct in supposing that female seahorses generally have fewer health problems than the males, Russell. There are a few different reasons for this.

First of all, the physiologically dynamic brood pouch of the males, with its heavy vascularization and increased blood supply, makes them much more prone to the various forms of Gas Bubble Syndrome (GBS) than females. On the other hand, female seahorses are highly resistant to GBS and are very rarely plagued by any forms of gas bubble disease. This is because they lack a marsupium. It is the physiologically dynamic, heavily vascularized, placenta-like brood pouch of the males that makes stallions prone to problems with GBS. This includes bloated pouch and chronic pouch emphysema, but also external and internal GBS. Such problems are seen almost exclusively in male seahorses.

Breeding males are often especially susceptible to chronic pouch emphysema and GBS in general because of the placenta-like changes that occur in the lining of the pouch during pregnancy. Spongelike, its tissues expand as the capillaries and blood vessels swell and multiply. A film of tissue then forms around each embedded egg, providing it with a separate compartment (alveolus) of its own. The thickening of the wall of the marsupium and elaboration of pouch structures around the implanted eggs result in a dramatic increase in vascularization, and this increased blood supply (hence increased concentration of carbonic anhydrase) transports more dissolved gases to the pouch, increasing the risk of GBS accordingly. The increased blood supply to the marsupium during pregnancy thus makes breeding males increasingly susceptible to the formation of intravascular gas emboli (micronuclei or seed bubbles) at this time, which can result in pouch emphysema and positive buoyancy problems.

Secondly, females obviously never have problems with prolapsed pouches. A prolapse or a partial prolapse of the pouch occurs when part of the lining of the marsupium becomes everted and protrudes through the mouth of the pouch. Prolapses can occur during or shortly after parturition as a result of the birth spasms during a strenuous delivery, or when courting males are performing their vigorous pouch displays and pumping water in and out of the pouch, or as a complication of recurring pouch emphysema.

Thirdly, males must occasionally deal with other complications of pregnancy, such as stillborn young that cannot be expelled, difficult deliveries that can sometimes extend over three or four days, and the inability to cleanse their pouch completely and flush out all the placental tissue fragments after delivering their brood. Pouch bloat can be caused by gas produced by the decay of embryonic material and the remains of placental tissue or other organic matter (possibly even stillborn young) within the brood pouch, if the male is unable to flush it out and cleanse it properly by pumping water in and out during its pouch displays (Cozzi-Schmarr, per. com.).

Finally, aggressive males occasionally injure one another when sparring for the right to a female. In the aquarium, both males and females compete for mates, but there is a big difference in the way they go about it. Females compete with one another passively, each trying to outdo the other and be the first to attract a mate simply by increasing the intensity of their courtship activities and displays. Their competitive behavior is therefore directed at the eligible males rather than any rival females. Males, on the other hand, compete much more actively and much more antagonistically. Their behavior is often aimed directly at their rival(s) and includes aggressive behaviors such as tail wrestling and snapping or sparring, which are never seen in the fairer sex. In other words, females respond to the presence of rivals by getting more flirtatious, whereas males often react to rivals by getting surly and carrying a testosterone-induced chip on their shoulders.

Snapping is an aggressive maneuver in which the attacker stretches out his head and flicks his snout against his rival with a violent snap, thus delivering a nasty blow to the foe. The snap is often aimed either at the opponent’s eye or gills — the only vulnerable spots on an armor-plated adversary — and the force of a well-directed snap can momentarily stun the unfortunate recipient. On very rare occasions, when these blows are directed at the head, eye injuries can result (mostly in the form of unilateral exophthalmia or Popeye), and persistent bullying can be stressful to the other seahorses.

So it is fair to say that female seahorses often experience fewer health problems than the stallions, Russell.

Best of luck with your stallions in the future, sir.

Respectfully,
Pete Giwojna, Ocean Rider Tech Support