Dear Lisa:
Woohoo! Congratulations on a very nice brood of Sunburst babies!
Now that your overdue dad has finally delivered his brood of young, he should also have purged himself of any gas that may have built up in his pouch over the course of his pregnancy. If not, he will expel it while pumping to cleanse his pouch when he re-mates within the next day or two.
Yes, you are correct regarding a four-week pregnancy. 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.)
The downside for the home breeder, of course, is that an extended pregnancy reduces the chances of premature newborns, or "half-cooked" babies that are still attached to their yolk sacs, and therefore makes it very challenging to identify and cull out the weaker fry from among a large brood. In your case, Lisa, it sounds like there are no obvious runts, preemies, or deformed newborns to weed out. When that’s the case, it’s cool to attempt to raise all of the healthy offspring. It just means that there are more mouths to feed, so you need to work that much harder in order to keep all of the newborns well fed.
As you know, the recommended stocking density for pelagic seahorse fry such as Mustangs or Sunbursts is no more than 6 fry per liter, or a maximum stocking density of about 25 fry per gallon. If your nursery tank holds 10 gallons, for example, it can hold about 200 newborns when stocked to capacity, and for best results I would keep it understocked. So for the time being, there should be no need to worry about larger accommodations for a healthy brood of over 100 fry, if you want to try to rear them all, Lisa.
Best of luck with your new Sunburst babies!
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.
