breeding reidi secret

Dear Michelle:

Don’t be too discouraged — Hippocampus reidi is a notoriously difficult species to raise, and few home hobbyists have much success with their initial rearing attempts regardless of the seahorse species. Brazilian seahorses reproduce so regularly that you will have lots of chances to refine your rearing techniques and work out methods that produce the best results for you.

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) gradually 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. I would be happy to recommend some good sources for nutritious live foods that would be ideal for this, if you like.

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.) 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. Just be sure to drop the water temperature very gradually (no more than 2°F daily). 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.

Bonus Tip: Jorge notes that the best way to rear reidi fry is by using circular black pseudo-kreisel nurseries with the flows being established by positioning a bubble curtain or a water jet at one end of the tank (Bull and Mitchell, 2002, p51). He cautions that the stocking density should be limited to no more than 80 fry per gallon (20 fry per liter) for the first two months (Bull and Mitchell, 2002, p51). After the second month, the juveniles will have passed through their pelagic phase and can be transferred to a regular rectangular rearing tank without turbulence or a circular kreisel flow for further growth and development (Bull and Mitchell, 2002, p51).

Water quality and photoperiod should be maintained as described above for the adult tanks, with 10% daily water changes and 150-200 Lux as the optimal light level (Bull and Mitchell, 2002, p51).

Bonus Tip: Jorge advises that turbidity is an important factor in the fry’s rearing environment. He uses a technique similar to greenwater nurseries to maintain the proper level of turbidity by adding algae (Isochrysis galvana) at a concentration of about 150,000 cells per ml (Bull and Mitchell, 2005).

Jorge finds that the optimal water flow for rearing reidi fry is 10 mm/sec, and he notes that feeding decreases at lower or higher flow rates (Bull and Mitchell, 2002, p51). At the proper level of flow (10mm/sec), the water movement also generates enough turbulence to break the surface tension of the water, allowing the newborn fry access to the surface where they will gulp enough air to inflate their swim bladders initially and achieve neutral buoyancy (Bull and Mitchell, 2002, p51).

If you contact me off list ([email protected]), Michelle, I will be happy to provide you with species summaries for H. reidi and seahorses with similar breeding habits that include rearing protocols developed for these difficult species by professional aquaculturists.

Best of luck with your prolific H. reidi and all of their progeny, Michelle!

Respectfully,
Pete Giwojna