Dust on my Seahorses?

Dear Haynes:

Welcome to the group! It’s good to hear that your Sunburst are doing so well. As long as you keep your water quality right where it should be and provide them with a nutritious diet, they should continue to thrive.

Yes, you bet — providing you fast them one day a week, it’s just fine if your Sunburst are eating more than the usual 2-7 Mysis each meal. 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 do whatever works bests for your seahorses and your schedule.

As you know, Haynes, the feeding regimen that generally works best for most captive-bred seahorses is to provide each of them with 2-7 frozen Mysis 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 needs to eat fewer shrimp than a pony that’s dining on the tiny Hikari 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 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. (We never want to see sunken, 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.)

Go ahead and let your young Sunbursts eat their fill, Haynes. Just be sure to fast them once a week as a precaution. Fasting your seahorses is important because they are otherwise prone to hepatic lipidosis, as discussed below.

Due to 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.

Avoiding overfeeding, fasting adults once a week and using relatively low-fat enrichment products such as Vibrance II for mature seahorses that are no longer breeding are simple ways to prevent fatty liver disease. If your Sunbursts don’t clean up all the Mysis you offer them at a single feeding within about 20 minutes, then you’re offering them too much.

No sir, Haynes, dust ordinarily does not settle on seahorses. There is one kind of disease, known as marine velvet disease or coral reef disease (Amyloodinium ocellatum), which can appear as a dust-like coating on fish, but I am quite confident that your seahorses don’t have this particular disease. Amyloodinium is caused by an ectoparasite that embeds itself into the skin of its host. The embedded parasites can appear as a dusting of very fine whitish are yellowish spots, but the "dust" would not be confined to the back of just one of your seahorses and you would not be able to simply wipe the parasites off. These parasites heavily infest the gills of their hosts, so they would be prevalent around the head and gills of your seahorses, and if you had an outbreak of Amyloodinium in your tank, both seahorses would be covered with a dustlike coating. Moreover, they would be off their feed, exhibiting respiratory distress and rapid breathing, and very likely be repeatedly attempting to scratch themselves with their tails. Since your seahorses have none of these symptoms and the dust is located only on the back of your female Sunburst, I think it is something else altogether. But before I go into that, here is some information on Amyloodinium for future reference:

Amyloodinium ocellatum (Marine Velvet, a.k.a. Coral Reef Disease)

Marine Velvet is another highly contagious disease caused by protozoal parasites. In this case, the parasites are dinoflagellates and Oodinium is fatal if untreated. These parasites attack the gills primarily, as well as the skin of their hosts, and the fresh-swimming stage of the Amyloodinium protozoans causes massive reinfection of aquarium fishes, leading to death by asphyxiation (Basleer, 2000). Typical symptoms include huffing and respiratory distress, excessive mucus production, and scratching (Basleer, 2000).

These unicellular parasites use their rootlike rhizoids to anchor themselves deep in the mucosa of their host (Basleer, 2000). They do their greatest damage to the mucosa layer, thus destroying the integrity of the fish’s slime coat. This weakens the fish’s first line of defense, leaving them susceptible to secondary infections that produces bloody red patches of skin in the advanced stages of the disease (Basleer, 2000). The characteristic dusting of fine white or yellow spots often never appears when seahorse’s are the hosts, making this condition difficult to diagnose for the seahorse keeper.

On other fishes, however, Amyloodinium appears as tiny white to yellow cysts. After several days, the encysted parasites drop off their host and divide into multitudes of daughter cells (Basleer, 2000). These daughter cells are known as the palmella stadium stage of the parasite, and they soon develop flagella and swim away as dinospores (Basleer, 2000). These dinospores are the infectious stage of the parasite. Hordes of them are released from each cyst and swarm through the aquarium, burrowing into the mucus layer of their victims and rooting themselves deeply in place (Basleer, 2000). The free-swimming dinospores must work fast. If they don’t embed in a new host within 24 hours they will die (Basleer, 2000). Massive reinfection of the gills is typically what kills aquarium fishes.

Positive identification can be made by microscopic examination. The Oodinium parasites are easily visible on skin or gill smears at a magnification of 100x or 200x power (Basleer, 2000). They appear as dark, cone-shaped unicellular organisms measuring 50-60 microns embedded in tissue (Basleer, 2000).

The traditional treatment for Marine Velvet is to treat the entire system with copper sulfate. A copper solution producing copper ions at a concentration of at least 0.20-ppm must be maintained for 8-10 days due to the complex life cycle of these parasites (Basleer, 2000). This will assure that all the free-swimming dinospores are killed as they emerge from cysts. Freshwater baths are generally used in conjunction with the copper sulfate, and antibiotic therapy may also be required if the skin was damaged to the extent that secondary infections have set in (Basleer, 2000).

As I mentioned, Haynes, I believe the dust you noticed on the dorsal surface of your Sunburst is most likely simply microalgae or diatoms growing on the skin, hence noting to be concerned about, rather than ectoparasites of any kind. That being the case, Haynes, it’s best not to attempt to physically remove such a coating. Although the algal growth can be unsightly, it is part of the seahorse’s natural camouflage; it can certainly be brushed away, but doing so risks removing the protective slim coat along with the algae which can have harmful consequences. Allow me to explain a little more about the seahorse’s skin and mucosa and the important purpose they serve:

We are all well aware that seahorses can change color to blend into their backgrounds, and that Hippocampus is capable of growing or shedding dermal cirri, which are long filaments and branching extensions of its skin, as called for in order to match its environment. To complete its disguise, the seahorse allows algae, bryozoans and other encrusting organisms to grow on its body, thereby rendering it all but invisible in its natural habitat. In fact, its skin contains polysaccharides which are believed to encourage algal growth, thereby helping it disappear into its surroundings. This vanishing act is so convincing that, even when they are collected by hand seining, seahorses often go undetected amidst the plant matter that accumulates in the net. Unless the collector is really diligent, he will lose a large proportion of his catch simply because many specimens will be overlooked and thrown back with the debris. In short, it’s perfectly normal for algae to grow on seahorses.

The seahorse’s pliant skin or integument is of course its first line of defense against disease. It contains mucus glands, and the slime covering the skin acts as a barrier to ectoparasites and infection. The protective slime can contain antibodies and antibacterial substances, and excessive mucus production is often the first sign of an infection or parasite problem. On the other hand, healthy seahorses often have small bright dots on their heads and torsos, which are actually mucus deposits. These beads of mucus glisten like little diamonds and are a sign of vibrant good health. When handling a seahorse, it’s important to wet your hands first in order to avoid removing too much of the protective slime coat.

Marine fish are always in danger of dehydration because the seawater they live in is saltier than their blood and internal body fluids. As a result, they are constantly losing water by diffusion (osmosis) through their gills and the surface of their skin, as well as in their urine. The mucus layer acts as a barrier against this, waterproofing the skin and reducing the amount of water that can diffuse across its surface.

So, all things considered, it’s best just to ignore any dust-like diatoms or microalgae that happens to grow on your seahorses. Removing it means removing the slime coat and mucous barrier as well, leaving the seahorse susceptible to infection and dehydration. It will secrete more mucous and repair its slime coat over the next day or two, but it will be vulnerable in the meantime.

In case you haven’t already seen them, Haynes, have been a few other threads on the Ocean Rider Club discussion board at seahorse.com from hobbyists who were just starting out with seahorses that you might find to be of interest. They discuss setting up an ideal system for seahorses, filtration, feeding, lighting, circulation and so on. I’ve provided links to those discussions for you below, so please check them out when I have a chance. I think they will help to answer many of your questions about keeping seahorses:

Re:Hello, newbie here! – O http://www.seahorse.com/option,com_simpleboard/Itemid,144/func,view/id,1004/catid,2/

Click here: Seahorse.com – Seahorse, Sea Life, Marine Life, Aquafarm Sales, Feeds and Accessories – Re:Setting up a 100gal for
http://www.seahorse.com/option,com_simpleboard/Itemid,144/func,view/id,1382/catid,2/

Re: Guidance on Keeping Seahorses:
http://www.seahorse.com/option,com_simpleboard/Itemid,144/func,view/id,639/catid,2/

Re: New to seahorses and I have lots of questions!
http://www.seahorse.com/option,com_simpleboard/Itemid,144/func,view/id,152/catid,2/

Re: Tank set-up advice
http://www.seahorse.com/option,com_simpleboard/Itemid,144/func,view/id,715/catid,2

Re:New with lots of questions 🙂
http://www.seahorse.com/option,com_simpleboard/Itemid,144/func,view/catid,2/id,1050/#1050

Best of luck with your new Sunbursts, Haynes! Keep up the good work!

Happy Trails!
Pete Giwojna