Re:male seahorses died

Dear Peg:

You’re very welcome! Yes, your suspicions were correct — a dreaded "vegetative event" is what caused the demise of your stallions when the bed of Caulerpa in the aquarium when sexual. That’s a rare recurrence and now that you have removed the Caulerpa there is no danger that this problem will repeat itself. As long as your females survived the initial emergency, they should suffer no ill effects now that the danger has passed.

Yes, waiting 30-60 days to make sure that your aquarium is back to normal should more than suffice. If all is well after 30-60 days, it would be a good idea to obtain some new mates for your female seahorses, but replacing the stallions is not an urgent need.

Although I have heard many anecdotal reports over the years that indicate that the health of a pair-bonded seahorse often suffers when it loses its mate, and that can no doubt be a dramatic event, the long-term health of the surviving seahorse is not at risk. Widowers are often said to languish, experience loss of appetite, and lapse into a general state of decline. Many hobbyists equate this to a state of depression or melancholy. While it’s safe to say that widowed seahorses don’t die from a broken heart, there may well be a kernel of truth at the heart of such accounts. It’s very likely that a pair-bonded seahorse suddenly separated from its mate will experience altered hormonal secretion as a result. This can cause low levels of certain hormones that are known to have a profound influence on both mental state and physical well being in humans and animals alike, affecting everything from the immune response to sperm production and sex drive.

So this is not a life-threatening development for your females, Peg, but domesticated seahorses like Mustangs and Sunbursts are highly social, gregarious animals that very much enjoy the company of others of their kind, and your mares may be happier in the long run if you can provide them with new potential mates and an opportunity to breed. In the meantime, your two females can keep each other company, so waiting 30-60 days to replace the stallions should not be a hardship at all.

Best of luck getting your seahorse tank back to normal again, Peg! It sounds like you’ve already done pretty much everything that’s necessary in that regard, but I would replace the activated carbon in your filter with fresh activated carbon (or add a good grade of activated carbon to the filter, if you aren’t already using it, as an added precaution).

Respectfully,
Pete Giwojna