Re:Feeding question…

Dear Barbie:

Is true that seahorses hunt more or less continuously throughout the daylight hours in the wild. This is because they are lay-in-wait "ambush predators" and it can take a long time for a suitable prey item to blunder within striking distance of them in the vastness of the ocean. So they are accustomed to eating small, bite-size meals at infrequent intervals throughout the course of the day in the wild.

But that’s not the case in the aquarium, where the attentive aquarist provides his or her prized ponies with all of the gourmet frozen Mysis they can eat once or twice daily. In other words, it doesn’t matter if the seahorses are being fed to satiety once or twice a day in the aquarium, or if they are very gradually filling up with many small mouthfuls spread out over the course of the day in the wild — in both cases their nutritional demands are being met quite nicely.

In short, Barbie, in the aquarium seahorses do not need to eat constantly, but rather do very well when they are given their fill of nutritious Mysis once or twice each day.

Having said that, it is also true that many seahorse keepers like to keep an abundant population of pods (i.e., copepods, amphipods, and the larval stages of various crustaceans) in their seahorse tank or an attached refugium in order to provide their ponies with an opportunity to graze on live prey between meals. But this is done primarily as a means of behavioral enrichment for the seahorses rather than to improve their nutritional support. Enriched frozen Mysis meets all of the long-term nutritional requirements of your seahorses and then some.

In fact, Barbie, frozen Mysis enriched with a good supplements such as Vibrance is such a nutritious diet — so high in unsaturated fatty acids and other lipids — that it is advisable to fast the seahorses one day a week in order to make sure they don’t get too much of a good thing. That’s why it’s customary to leave the seahorses unfed one day each week, in order to safeguard their health and well being.

Because of their lazy lifestyle, our pampered pets are susceptible to a debilitating affliction commonly known as "fatty liver disease" or hepatic lipidosis when they are given a diet that’s excessively rich in HUFA (highly unsaturated fatty acids) and other lipids. Mature seahorses that are no longer breeding are at greatest risk from hepatic lipidosis. Young seahorses need a high-fat diet to sustain their rapid growth and development, and breeding pairs that are churning out brood after brood of fry likewise need all the energy they can get. But once they reach sexual maturity, their growth rate slows markedly, and nonbreeding adults that receive a high-fat diet will begin to store excess fat in specialized cells called adipose tissue (Tamaru, Sep. 2001). Eventually these fatty deposits will begin to infiltrate the liver cells, hence the name fatty liver disease (Tamaru, Sep. 2001).

In severe cases, adipose tissue can become so thick that it can literally hides the internal organs, cloaking them within a cocoon of fat, and distending the abdomen (Tamaru, Sep. 2001). When the seahorse’s liver or hepatopancreas becomes badly infiltrated with fatty deposits, it interferes with the organ’s ability to perform its vital role in digestion, food absorption, and detoxification of the blood, which has dire consequences for the affected seahorse.

Fasting one day a week helps prevent such problems, but providing our ponies with a good meal of unfed, unfortified adult brine shrimp, which has negligible fat content, works just as well in terms of protecting seahorses from fatty liver disease. That’s what I prefer to do, rather than fasting my seahorses.

What I’m trying to say, Barbie, is that many seahorse keepers like to offer their ponies live prey at times as occasional treats because it is healthy and fun for the seahorses to chase down the live food, and entertaining and fun for the aquarists to watch them do so. But this is done in order to provide the seahorses with a welcome diversion rather than as a necessity…

In a nutshell, providing occasional meals of live prey is good behavioral enrichment for our seahorses. As you know, I feel Hippocampus is intelligent enough to become bored or jaded in captivity at times, and for this reason I think it’s important to provide them with a change of pace and liven things up for them once in a while. Imagine how tiresome it would be if you had to eat the same thing for every meal day after day for the rest of your life. No matter how nutritious the meals may be, dining on the same thing every day would eventually make your meal times pretty uninteresting. The handfeeding sessions I engage in with my seahorses help to break up the daily routine, and I also try to provide my seahorses with live foods regularly so they have an opportunity to experience the thrill of the hunt and the chase once in a while as they do in the wild.

So nowadays, rather than fasting my seahorses once a week, I offer them a meal with a nutritional value that’s virtually nil instead: unenriched, unfed adult brine shrimp. As you can imagine, brine shrimp in this condition have very little fat content and should be considered nutritionally barren for all intents and purposes. Feeding them the brine shrimp a fun alternative to fast days that I feel is far easier on the hobbyist and his pampered pets alike.

So once a week, instead of depriving my seahorses, I now serve them up a generous portion of unenriched adult brine shrimp. They get the thrill of hunting and eating live food and I get the fun of watching them chase after it. Instead of going hungry, my seahorses get to fill up on empty calories, while I get to avoid a guilty conscience. It’s a win-win situation. Everybody’s happy.

It’s a neat way of "fasting with a full belly," which I feel is healthy for the seahorses in more ways than one. Not only does it help guard against hepatic lipidosis from a high-fat diet, it also provides a little extra excitement for the seahorses and helps improve their quality of life in captivity.

That’s why many seahorse keepers prefer to provide their ponies with unenriched adult brine shrimp, or similar live fodder, once a week rather than fasting them — it’s fun for both the seahorses and their owners, and does just as good a job of helping to prevent fatty liver disease.

This is what I normally advise home hobbyists regarding feeding their seahorses, Barbie:

<open quote>
Feeding & Enriching Frozen Mysis

There is no simple answer to the question, "How many frozen Mysis should each of my seahorses be eating per day?" That depends on the size of the frozen Mysis, which varies considerably from brand to brand, the size of the seahorses themselves, and the size of their appetites, which is also quite variable from one pony to another, as well as a number of other factors. Mustangs and Sunbursts (Hippocampus erectus) of average size usually eat between 2-7 of the big Piscine Energetics Mysis relicta per feeding, but rather than trying to keep track of how many frozen Mysis each of your seahorses has eaten, it’s a better idea to check them for well-rounded abdomens after they have eaten a big meal and to observe their fecal production in order to make sure they are all getting enough to eat on a daily basis, as discussed below.

In addition to cycling your aquarium and setting it up to create an ideal environment for seahorses, you will also need to line up a good source of frozen Mysis before your seahorses arrive. Frozen Mysis is available in several different brands from a number of different sources. Gamma brand frozen Mysis is good, Hikari frozen Mysis is quite acceptable (although often fragmentary) as is San Francisco Bay brand frozen Mysis and the Omega One Mysis, whereas the Mini Mysis by H2O Life is great for small seahorses, and Piscine Energetics frozen Mysis is no doubt the best in terms of nutritional content and quality control. Your local fish stores should carry one or more of these brands.

I have noticed that seahorses can sometimes be very selective when it comes to the size of the prey they prefer. For instance, the jumbo PE Mysis relicta are of course quite large, and it’s certainly possible that young seahorses may balk at the jumbos simply because of their size. Some seahorses are very particular in that regard, and tend to reject food items that are significantly larger or smaller than their preferred range of prey. For example, I’ve seen some seahorses that rejected the smaller Hikari Mysis with great disdain, yet which greedily gulped down the jumbo Piscine Energetics Mysis relicta. On the other hand, I’ve had small seahorses turn up their snouts at the jumbo PE frozen Mysis because it’s too large for their liking, and attack the small Hikari frozen Mysis with great gusto.

Whatever brand of frozen Mysis you obtain, for best results, it’s a good idea to fortify it with Vibrance before feeding it to your seahorses. Vibrance is an enrichment formulation that was designed by a research team of nutritionists and fish biologists especially for use with frozen Mysis shrimp in order to meet the dietary requirements of seahorses, and it has been developed specifically to provide a long-term balanced diet for these unique fishes. Depending on which Vibrance formulation you use, it includes additional highly unsaturated fatty acids (especially the DHA Omega 6 DHA series), along with Vitamin C and essential minerals, in the proper proportions to further enhance the nutritional profile of the protein-rich frozen Mysis. Studies indicate the DHA it includes is essential for high survivability, nerve development, stress management, and proper reproduction. Vibrance is a bright red-orange powder that gets its characteristic color due to its high content of carotenoids, which are an abundant source of Vitamin A and act as natural color enhancers for yellow and red pigmentation. It is the only enrichment product that includes beta glucan as an active ingredient. That’s important because beta glucan is a potent immunostimulant that provides important health benefits for fish.

In order to enrich it, the frozen Mysis is carefully thawed out and rinsed well to remove any excess shrimp juices, and then a VERY light dusting of the Vibrance is added to the Mysis while they are still just a bit moist. The Vibrance is then gently worked into the frozen Mysis and it usually adheres very well. The end result should be whole, completely intact Mysis shrimp that have acquired a reddish tinge to their head or anterior end. In actual practice, there are probably as many different ways of successfully thawing and enriching frozen Mysis as there are aquarists that use them; most everybody works out their own method of preparing the frozen Mysis that works best for their needs and busy schedule.

Here are Ocean Rider’s usual feeding suggestions to guide you at mealtime:

Feeding Tips

In general, it’s a good idea to offer one morning feeding and one mid-to-late afternoon feeding, if possible, but there are no hard-and-fast rules when it comes to easy-to-feed, farm-raised horses. Some hobbyist prefer to give their seahorses two feedings a day, while others prefer to give them their quota of frozen Mysis in one big meal. As long as they get their fill, there is really no right or wrong way to go about this — just stick with whatever works bests for your particular ponies and their eating habits as well as your busy daily schedule.

As you know, the feeding regimen that generally works best for most captive-bred seahorses is to provide each of them with 2-7 frozen Mysis relicta twice a day, enriched with Vibrance, and then to fast your seahorses entirely once a week. In other words, your seahorses should each be eating a total of around 4-14 frozen Mysis each day, depending on the size of the seahorse and the size of the Mysis. But those are just rough guidelines and there is a lot of variation in how much Mysis healthy seahorses eat each day.

A large seahorse naturally eats more than a smaller pony. And jumbo-sized Mysis will fill up a hungry seahorse faster than smaller shrimp. So a seahorse that’s scarfing up king-sized Piscine Energetics Mysis relicta does indeed need to eat fewer shrimp than a pony that’s dining on the tiny Hikari Mysis or the miniscule H2O Mini Mysis.

Aside from size, some of the other factors that determine how much a seahorse eats are water temperature, the age of the seahorse, and whether or not it is actively breeding at the moment. The warmer the water temperature (within the seahorse’s comfort zone), the higher it’s metabolism, and the more calories it needs to eat as a result. Young seahorses that are still growing rapidly typically eat more than mature seahorses that have reached their full growth. As you might expect, breeding pairs that are producing brood after brood every few weeks need to eat a lot because so much of their bodily resources go towards producing clutches of eggs or nourishing a pouch full of developing young.

So don’t get hung up trying to count every morsel every seahorse in your tank scarfs down. Just make sure all your seahorses have full bellies at the end of the day, as indicated by their well-rounded abdomens. After a good feeding, the seahorses belly rings should be flush or even slightly convex in cross section when viewed from head on. (We never want to see sunken, severely pinched-in abdomens on our seahorses! Concave belly rings are a sure sign of an underfed seahorse, with the sole exception of a female that has just transferred her eggs.)

So if you want to check whether your seahorses are eating well or not, don’t look at their profile — just examine them head-on and check out their gut. Their abdomens or belly plates should bulge out slightly or at least be flush with their flanks, not pinched in or sunken. In other words, when viewed from the back or from head-on after a good feeding, the cross-section of their abdomens should appear convex "( )" or flush "l l" rather than concave ") (" or pinched in.

Another good way to tell if your seahorses are getting enough to eat is by observing their fecal production. Ponies that are producing well-formed fecal pellets regularly are receiving good nutrition.

The recommended feeding regimen is to provide each of your seahorses with 4-14 frozen Mysis shrimp daily, enriched with a good food supplement, and then to fast your seahorses entirely once a week. Some hobbyists prefer to give their seahorses two or more feedings a day, while others prefer to give them their quota of frozen Mysis in one big meal. As long as they get their fill, there is really no right or wrong way to go about this — just do whatever is most convenient for you and also keeps the ponies fat and sassy.

However, many hobbyists find that their seahorses feed best during the morning, so if you can only feed your seahorses once a day, try to make it a morning meal. Whether it’s their biological clocks, something built into their natural circadian rhythm, or whether they’re simply hungriest shortly after waking up, seahorses do seem to feed more aggressively in the morning, and hobbyists should try to accommodate them, if possible. Breakfast, it seems, is the most important meal of the day for our aquatic equines as well as ourselves.
<Close quote>

Okay, Barbie, that’s the quick rundown on feeding seahorses with frozen Mysis. Suffice it to say that you do not need to worry about feeding seahorses constantly; they will thrive as long as you give them their fill of frozen Mysis once or twice a day. Feel free to offer them live treats on occasion as a way to enrich their quality of life in the aquarium, but it is not necessary to do so in order to meet their nutritional requirements.

Happy Trails!
Pete Giwojna