White Flakes on Skin

Dear Tempest:

I am not quite sure what to make of the white flakes you noticed on the skin of your seahorses. Can you possibly give me a little better description of these flakes?

If you mean that in some areas the skin of the seahorses is beginning to peel up and flake off, that’s an indication of ulcerative dermatitis, a serious bacterial infection that should be treated in isolation with broad-spectrum antibiotics. Is the skin itself lifting up and peeling off or flaking, Tempest? If so, how does the skin appear underneath the flakes that are peeling off? Is it red and inflamed? Bloody? Discolored?

Or do you mean that some sort of white precipitate is settling out of the water in flakes that adhere to the skin of your seahorses? Or are you describing excess mucus or portions of the slime coat that are sloughing off the back and tails of the seahorses?

Do all of the seahorses and fish in the aquarium have the white flakes, or is it only two of them? Do the affected seahorses have any other symptoms of a problem other than the white flakes on their skin? Itching or scratching? Any signs of respiratory distress (e.g., huffing or panting, labored breathing, rapid respirations)? Loss of appetite or lethargy or cloudy eyes or reduced eye movement?

I need more information about your aquarium system and the appearance of these white flakes in order to determine what kind of a problem your seahorses may be experiencing. Please get back to me as soon as possible with more information about the flakes and your current readings for the following aquarium parameters:

Ammonia (NH3/NH4+) =
Nitrite (N02) =
Nitrate (N03) =
pH =
specific gravity or salinity =
water temperature =

It would also be very helpful if you could send me one or two digital photographs that provide a close-up look at the white flakes you are concerned about. If possible, please insert photographs of the affected seahorses in an e-mail and send it to me off list ([email protected]), along with additional information about your seahorse setup.

Good luck in the meantime, Tempest!

Respectfully,
Pete Giwojna

Dear Tempest:

Thank you very much for the additional information — it really helps clarify matters.

The itching and scratching of the seahorses, and the fact that the white specks seem more like white dots, and the skin is not peeling off or flaking away, suggest that you may be having a problem with external parasites, rather than a bacterial infection.

I would suggest that you perform a diagnostic freshwater dip on the affected seahorses as soon as possible and then line up a good antiparasitic medication they can be added safely to your main tank. The freshwater dip can provide the itchy seahorses with some immediate relief from embedded ectoparasites, and examining the water in the dipping container afterwards can help confirm that parasites are the culprits in this case.

Here are the instructions for performing a freshwater dip safely, Tempest:

Freshwater Dips

A freshwater dip is simply immersing your seahorse in pure, detoxified freshwater that’s been preadjusted to the same temp and pH as the water the seahorse is accustomed to, for a period of at least 10 minutes (Giwojna, Dec. 2003). It doesn’t harm them — seahorses typically tolerate freshwater dips exceptionally well and a 10-minute dip should be perfectly safe. Freshwater dips are effective because marine fish tolerate the immersion in freshwater far better than the external parasites they play host to; the change in osmotic pressure kills or incapacitates such microorganisms within 7-8 minutes (Giwojna, Dec. 2003). A minimum dip, if the fish seems to be doing fine, is therefore 8 minutes. Include some sort of hitching post in the dipping container and shoot for the full 10 minutes with your seahorses (Giwojna, Dec. 2003).

If you will be using tap water for the freshwater dip, be sure to dechlorinate it beforehand. This can be accomplished usually one of the commercial dechlorinators, which typically include sodium thiosulfate and perhaps a chloramine remover as well, or by aerating the tap water for at least 24 hours to dissipate the chlorine (Giwojna, Dec. 2003).

If you dechlorinate the dip water with a sodium thiosulfate product, be sure to use an airstone to aerate it for at least one hour before administering the dip. This is because the sodium thiosulfate depletes the water of oxygen and the dip water must therefore be oxygenated before its suitable for your seahorse(s). Regardless of how you detoxify the freshwater for the dip, it’s important to aerate the water in the dipping container well beforehand to increase the level of dissolved oxygen in the water. Many hobbyists leave the airstone in the dipping container throughout the procedure.

Adjusting the pH of the water in the dipping container so that it matches the pH of the water in the aquarium is a crucial step. Ordinary baking soda (sodium bicarbonate) will suffice for raising the pH of the water. If there is too much of a difference in the pH, there is a possibility the seahorse could go into shock during the dipping procedure. Preadjusting the pH will prevent that from happening. If you will are unsure about your ability to accurately adjust the pH in the dipping container, avoid this procedure altogether or be prepared to monitor the seahorse very carefully or shorten the duration of the tip to no more than about 4 minutes.

Observe the horse closely during the dip. You may see some immediate signs of distress or shock. Sometimes the horse will immediately lie on its side on the bottom. That’s a fairly common reaction — normal and to be expected, rather than a cause for concern, so don’t be alarmed if this happens. Just nudge or tap the seahorse gently with your finger if it lies down on its side. Normally, the seahorse will respond to the slight nudge by righting itself again and calm down for the duration of the dip. However, if it does not respond, stop the treatment.

Most seahorses tolerate the treatment well and experience no problems, but if you see continued signs of distress — twitching, thrashing around etc. — stop the treatment.

After you have completed the dip and returned the seahorses to the aquarium, save the dip water and examine it closely for any sign of parasites. The change in osmotic pressure from saltwater to freshwater will cause ectoparasites to lyse (i.e., swell and burst) or drop off their host after 7-10 minutes, and they will be left behind in the dipping water. Protozoan parasites are microscopic and won’t be visible to the naked eye, but some of the other ectoparasites can be clearly seen. For example, monogenetic trematodes will appear as opaque sesame seeds drifting in the water (Giwojna, Aug. 2003) and nematodes may be visible as tiny hairlike worms 1/16-3/16 of an inch long. Other parasites may appear as tiny dots in the water. Freshwater dips can thus often provide affected seahorses with some immediate relief by ridding them of these irritating pests and can also aid their breathing by flushing out gill parasites.

If you suspect a problem with parasites, the dip should be extended for the full 8-10 minutes if possible for best results.

I would not dip all of the seahorses simultaneously, Tempest. Rather, I would dip them individually so you can keep a close eye on each seahorse throughout the dip and make sure it is tolerating it well. That way, you can use the same dipping container and dipping water for all for seahorses as you dip them in sequence. Return each of the seahorses to the main tank after their dip, and examined the dipping water left behind in the container closely afterwards for any visible ectoparasites (a magnifying glass or, better yet, a microscope is very helpful for this.)

Be sure to observe the following precautions when you are handling the seahorses for the freshwater dips, Tempest:

Handling Seahorses

I do not like to use an aquarium net to transfer or manipulate seahorses, since their delicate fins and snouts can become entangled in the netting all too easily. I much prefer to transfer the seahorses by hand. Simply wet your hand and fingers (to avoid removing any of the seahorse’s protective slime coat) and scoop the seahorses in your hand. Allow them to curl their tail around your fingers and carefully cup their bodies in your hand to support them while you lift them out of the water. When you gently immerse your hand in the destination tank, the seahorse will release its grip and swim away as though nothing out of the ordinary has happened.

Composed of solid muscle and endowed with extraordinary skeletal support, the prehensile tail is amazingly strong. Indeed, large specimens have a grip like an anaconda, and when a 12-inch ingens or abdominalis wraps its tail around your hand and tightens its hold, its vise-like grip is powerful enough to leave you counting your fingers afterwards!

In fact, it can be quite difficult to remove an attached seahorse from its holdfast without injuring it in the process. Never attempt to forcibly detach a seahorse from its hitching post! When it feels threatened, it’s instinct is to clamp down and hold on all the tighter. When you must dislodge a seahorse from its resting place for any reason, it’s best to use the tickle technique instead. Gently tickling the underside of the tail where it’s wrapped around the object will usually induce the seahorse to release its grip (Abbott, 2003). They don’t seem to like that at all, and will quickly let go to move away to another spot. Once they are swimming, they are easy to handle.

In the meantime, I will keep an eye out for the photographs and information regarding your water quality parameters, Tempest. Please get the photographs in particular to me as soon as possible. Once I examined the photos and I have heard if the freshwater dips provided the seahorses with any relief or revealed any ectoparasites left behind in the dipping container, I can advise you as to appropriate medication for eradicating this infestation.

Respectfully,
Pete Giwojna