Major temperature changes

Dear hobbyist:

Well, if your seahorse is Hippocampus erectus, which is the most commonly kept species in the United States, then it can tolerate a gradual temperature drop down to 55° F without any harmful effects. As long as you adjust your temperature back to normal gradually, say raising it just a few degrees daily, or even simply allowing it to gradually adjust to the ambient room temperature without the use of an aquarium heater, the chances are good that your ponies will be fine.

The reason for this is that Hippocampus erectus is a seahorse of many different temperatures. With an enormous range that extends all the way from Canada to Brazil, crosses a great deal of latitude, and overlaps 4 different climatic belts, this species tolerates an equally wide range of temperatures. Specimens of erectus from Nova Scotia are verging on subtemperate conditions, but a bit further south (i.e., the New England and midAtlantic States of the US), it’s a temperate seahorse; Florida erectus are subtropical and still further south, in Central America and the Caribbean, it’s a tropical species. And in parts of South America, erectus is accustomed to torrid equatorial conditions. You may thus see H. erectus correctly described in the literature as everything from temperate to tropical; some references say it is a cold-water seahorse and others describe it as a warm-water seahorse. Perhaps you have been confused by such apparent contradictions in the past. Don’t be. All the sources are correct, and all the various descriptions are accurate. The temperature requirements for H. erectus simply vary depending on where the seahorses originated. Specimens from Chesapeake Bay need cooler water than seahorses from Florida or the Gulf of Mexico. This is reflected in Dave Littlehale’s information, in which public aquaria reported keeping H. erectus successfully at temperatures ranging from 55°F-82°F (13°C-22°C) (Bull and Mitchell, 2002, p33). If acclimated carefully, these hardy seahorses will thrive under either temperate or tropical conditions.

Best of luck with your seahorses. Power outages are the bane of all fish keepers; if you like, I would be happy to discuss some of the precautions that home aquarists can take if they live in an area prone to outages, blackouts, and brown outs to prevent such disasters in the future.

Respectfully,
Pete Giwojna, Ocean Rider Tech Support

Dear hobbyist:

That’s most unfortunate that two of your Hippocampus erectus also succumbed as a result of a power outage.

But, as we have been discussing, Hippocampus erectus can adapt to a very wide range of water temperature as long as the temperature changes are gradual enough. So if the other ponies are eating and looking fine despite the dramatic drop in water temperature, then I suspect they will be okay as long as you do not raise the water temperature too quickly. Be sure to take your time when raising the aquarium temperature.

One other thing to beware of is a spike in the ammonia or nitrite levels in the aquarium. It sounds like the power outage wiped out all of the fish in the tank except for some of the ponies, and if there have been any dead snails or other invertebrates whose loss may have gone undetected, that could cause your water quality to deteriorate. The sudden change in water temperature may also have had an adverse effect on the beneficial nitrifying bacteria that provide biological filtration, so be sure to keep a close eye on your water quality parameters.

Good luck.

Respectfully,
Pete Giwojna, Ocean Rider Tech Support