Well, sir, if you are very careful when acclimating the seahorses to the lower temperature, your Sunbursts (Hippocampus erectus) could certainly tolerate a stable water temperature of 68°F-70°F. Ideally, you don’t want to drop the water temperature more than 2°F daily, since temperature fluctuations greater than that begin to become stressful for the seahorses. But as long as you step down the water temperature very gradually over a period of several days, then that is certainly doable, even though Ocean Rider Sunbursts are tropical seahorses. Allow me to explain.
Hippocampus erectus is a seahorse of many different temperatures, Ray. With an enormous range 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.
However, bear in mind that the optimum temperature range for Sunbursts (Hippocampus erectus) is 72°F-75°F, and bear in mind that they are cold-blooded animals so keeping them in cooler water at 68°F-70°F will therefore lower their metabolism. They will very likely be less active than normal and eat less frozen Mysis each day as a result. One thing I am unsure about is whether or not the lower water temperatures will have any affect on the coloration of the Sunbursts, Ray. They will darken in response to stress, including heat stress, but I don’t know if the other temperature extreme will be stressful enough to have an adverse impact on their coloration or not…
On the other hand, the cooler water temperatures will help protect the ponies against bacterial infections, since cooler water temperatures reduce both the growth rate and virulence of pathogenic bacteria such as Vibrio, so that’s a plus, Ray.
Best wishes with all your fishes, Ray!
Pete Giwojna, Ocean Rider Tech Support