Dear Michelle:
Congratulations on your prolific pair of Brazilian seahorses (Hippocampus reidi)!
Yes, it is true that gradually reducing the water temperature will extend the gestation period for your seahorses and, if I was you, Michelle, I would concentrate on two main things to increase the survivorship of your H. reidi fry: (1) providing your breeding male and female — your all-important broodstock — with the very best possible nutrition, and (2) reducing the water temperature in your H. reidi tank somewhat in order to prolong the gestation period of your stallion. We now have considerable evidence that providing the male and female with a very nutritious diet results in a larger average size for the newborns, which enjoy increased survivorship/lower mortality rates as a result. Jorge Gomezjurado found that providing his H. reidi and H. ingens broodstock with a very nutritious diet increased the size of the newborns to the point that they could accept newly hatched brine shrimp for their first food. So I would give your breeding male and female a steady diet of Piscine Energetics frozen Mysis relicta enriched with lipid-rich Vibrance 1, and then provide them with regular feedings of enriched live foods as well.
As far as reducing the water temperature, as you know, the lower the water temperature, the longer the gestation period in Hippocampus. And a prolonged pregnancy does indeed have benefits for the developing young. For example, the Birch Aquarium at the Scripps Institute of Oceanography finds that maintaining locally obtained H. ingens at cooler water temperatures extends the gestation of gravid males and increases survivorship of their pelagic fry (Liisa Coit, pers. com.). Lowering the water temperature, hence prolonging the gestation, increases the incubation period for the fetal fry and embryonic young the gravid male is carrying, which in turn translates into larger, more developed fry. The bigger, better developed newborns that result can feed and swim more efficiently and their survival rates are increased accordingly (Liisa Coit, pers. com.). So I would keep the water temperature in the comfort range for your H. reidi, but at the lower end of the range rather than the upper end of the range. They typically do best between 72°F-78°F, so try gradually reducing your water temperature to see if that produces the desired results. Normally, H. reidi give birth after a brief 14 day gestation period, and if you can extend that for just a few days by manipulating the water temperature, it can make a big difference.
Try to reduce the water temperature in the main tank gradually, no more than 2°F per day, and see if you could stabilize the temperature at around 70°F. That may require an aquarium chiller, but lowering the water temperature several degrees should certainly increase the gestation period for your prolific ponies and produce larger newborns with a better chance of survival.
Best of luck raising this most challenging species, Michelle! If you contact me off list ([email protected]), I can provide you with some additional tips and suggestions for raising H. reidi fry.
Happy Trails!
Pete Giwojna
Ocean Rider, Inc. is an Organic Hawaiian-Based Seahorse Aqua-Farm & Aquarium that Follows Strict Good Farming Practices in Raising Seahorses and Other Aquatic Life.
