My first thought is that your new Hippocampus erectus probably just needs a little more time to get adjusted to her strange new surroundings and start to feel at home before she resumes feeding normally again.
Another thing that could be contributing to the loss of appetite is a decline in the water quality in your quarantine tank. Be sure to check your water quality often to make sure there hasn’t been a spike in the ammonia or nitrate levels.
In the meantime, it might also be a wise precaution for you to line up some live foods to tempt your finicky seahorse and see if you can fatten it up a bit. When a seahorse stops eating, the most important thing is to get some food into him one way or another. You’ve got to keep his strength up and give it a chance to recover before you can worry about weaning the seahorse back onto frozen foods again. Hawaiian red feeder shrimp or volcano shrimp (Halocaridina rubra) are ideal for this — seahorses find them utterly irresistible! But anything that’s readily available — enriched adult brine shrimp, live ghost shrimp that are small enough to be swallowed, newborn guppies or mollies, Gammarus amphipods, copepods, you name it — is worth a try. Just get some good meals into the reluctance seahorse ASAP anyway you can to build up its strength and help it regain its conditioning.
When seahorses tire of the same old, boring frozen food and refuse to eat their “veggies,” living prey is what they crave: Mysids, feeder shrimp, Gammarus or adult Artemia — the type of food isn’t really as important as the fact that it’s alive and kicking. Nothing stimulates a sea horse’s feeding instincts like the frantic movements and evasive maneuvers of real, live, “catch-me-if-you-can” prey items (Giwojna, 1996).
That’s why I like to use occasional treats of live food as behavioral enrichment for my seahorses. They get the thrill of hunting after and chasing down live prey, which livens things up for them in more of ways than one and is a nice change of pace from their daily routine in captivity. Live foods are guaranteed to perk up an ailing appetite and excite the interest of the most jaded “galloping gourmets.” When it comes to a hunger strike, living prey is the only sure cure for the “Bird’s Eye blues.” (Giwojna, 1996)
I also find live foods to be especially useful for those rare occasions when seahorses are ailing and must be treated. Many medications (e.g., Diamox) have the unfortunate side effect of suppressing appetite, so when treating sickly seahorses, it’s a good idea to tempt them with choice live foods in order to keep them eating and help build up their strength while recuperating. Separating an ailing seahorse from its mate and herdmates and transferring it to a strange new environment for treatment can be a traumatic experience, especially since the Spartan surroundings in the sterile environment of a sparsely furnished hospital tank can leave a seahorses feeling vulnerable and exposed. Live foods can counteract these negative affects to a certain degree, and offer a little excitement that distracts the isolated seahorse temporarily at least from its melancholy.
Some of the choice live foods that sea horses find irresistible are Ocean Rider’s red feeder shrimp (Red Iron Horse Feed, Halocaridina rubra), Gammarus amphipods, and the live Mysis post-larval Feeder Shrimp from Sachs Systems Aquaculture or Drs. Foster and Smith (liveaquaria.com). These live bite-size crustaceans are what I’d like to call a “feed-and-forget” food. They are tough, rugged little shrimp that you can toss in your tank with no acclimation whatsoever. They are agile and elusive enough that your filters won’t eat them and the seahorses won’t be able to capture them all right away. Some will hide and evade well enough that your seahorses will still be hunting down the stragglers for the next day or two. Best of all, you can toss a nice batch of them in your aquarium, secure in the knowledge that they won’t perish and pollute it, but thrive and survive as real, live, “catch-me-if-you-can” prey items that seahorses cannot resist.
When a seahorse goes off its feed, providing it with choice live foods can buy you time and stave off starvation while you work on making the water changes to assure optimal water quality for your seahorses.
The Ocean Rider Aquaculture Facility in Hawaii (http://seahorse.com/) is a good source for the following live foods:
Green Iron Horse Feed (Gammarus amphipods)
Red Iron Horse Feed or Volcano Shrimp (Halocaridina rubra)
Or the live Mysis from Sachs Systems Aquaculture would also be a good choice for this. You can obtain 200 live Mysidopsis bahia for around $35 from Sachs and your seahorses will love them:
Likewise, the live Mysis or post-larval Feeder Shrimp from Drs. Foster and Smith would also be a good alternative for you, Ray. You can obtain 100 live Mysidopsis bahia for $33.99 or 100 bite-size Feeder Shrimp for $39.99 from liveaquaria.com and your seahorses will love them. Just copy the following URL (everything within the angle brackets below), paste it in your web browser, and press the “Entered” key, Ray, and it will take you directly to the right webpage:
Some hobbyists have good success coaxing a finicky seahorse to feed by transferring the seahorse to a critter keeper or breeder net or similar enclosure that can hang within the main tank itself, and then adding a generous portion of live feeder shrimp to the container. Within the enclosure, the affected seahorse does not have to compete with its tankmates for the live food, and it is easy to maintain an adequate feeding density within the confined space so that there is always a bite-size feeder shrimp passing within striking distance of the hungry seahorse. If the affected seahorse is still interested in feeding at all, then releasing it in an in-tank enclosure like this where it will be surrounded by plenty of tempting live feeder shrimp and can feed at its leisure may help it to keep its strength up and recover more quickly. Add one or two hitching posts within the critter keeper or breeder net so that the seahorse can anchor in place and wait for a tasty shrimp to pass within easy reach, and give him an hour or two within the enclosure to eat his fill of the feeder shrimp. You can monitor his progress from a nonthreatening distance away from the tank to see how he is doing. In most cases, the seahorse quickly becomes familiar with the routine of being transferred to the special enclosure at feeding time and associates it with tasty live foods and a full belly — positive reinforcements that make it a very nonthreatening, stress-free procedure for the affected seahorse — and, as a result, it may actually come to look forward to it after a few feedings. You can repeat this feeding process two or three times daily in order to fatten him up again, if your schedule allows.
Best of luck getting both of your new ponies back eating like horses again, Triinsept.
Pete Giwojna, Ocean Rider Tech Support