Pete Giwojna

Dear Seagazer:

Wow, that’s a nice problem to have — needing more space because you’re getting overrun with homegrown seahorses, I mean! Congratulations on your outstanding rearing success, sir!

Regarding the problem with the damselfish that you are using to cycle your new 30-gallon tank and which have developed saltwater ich (Cryptocaryon irritans), I would not just let the disease run its course. The problem with that approach is that the life cycle of this protozoan parasite includes a very tough encysted stage (i.e., the tomonts) that can persist for several weeks on the bottom of the tank before they rupture and release the infectious stage of the parasites (tomites) which then seek out new fish to reinfest. So if you simply allow this outbreak of Cryptocaryon to run its course, there’s a very great risk that your juvenile seahorses will become infested when you subsequently introduce them to the aquarium. Allow me to explain a little more about Cryptocaryonosis so you can understand why it’s important to treat the tank and eradicate these parasites.

Cryptocaryon is commonly known as saltwater ich or white spot disease. It is caused by a protozoan parasite that burrows into the skin and gills of its host and is one of the most common diseases of marine fishes. Most hobbyists who keep saltwater fish are all too familiar with Cryptocaryon. In the confines of the aquarium, massive reinfestation with these parasites occurs, making Cryptocaryon deadly if left untreated.

In seahorses, it often occurs as a masked infection. The bony exoskeleton and protective slime coat of Hippocampus gives the seahorse limited immunity from the burrowing trophonts, so the telltale white spots may never show up (or may be visible only on the unarmored fins). But the parasites can still freely invade the seahorse’s gills, with deadly results.

Here’s an excerpt on Cryptocaryon from my new book (Complete Guide to the Greater Seahorses in the Aquarium, TFH Publications, unpublished) that discusses various treatment options:

Cryptocaryon irritans (Saltwater Ich, a.k.a. White Spot Disease)

Cryptocaryon is another protozoal parasite that invades the gills and burrows into the skin of marine fishes, including seahorses. The life cycle and modus operandi of Cryptocaryon are very similar to that of Amyloodinium ocellatum, so it should not be surprising that it also produces strikingly similar symptoms. Infected fish show labored breathing, excess mucus, and scratch themselves against objects. Along with the characteristic pinhead-sized white spots and excess mucus production, affected fish sometimes show cloudy eyes and secondary infections (Basleer, 2000). The latter can result in skin rot and fin rot accompanied by red or pale patches on the body of the fish (Basleer, 2000).

The white spots seen on infected fish are the adult stage of the parasite, known as trophonts (Basleer, 2000). When they mature, they fall off the fish and encyst themselves. The encapsulated parasites are known as tomonts (Basleer, 2000). Well protected within these cysts, the tomont stage cannot be killed by any medications. The encapsulated tomonts divide into hundreds of daughter cells, which develop into small, ciliated, free-swimming parasites, called tomites (Basleer, 2000). When the cysts rupture, the motile tomites swarm out to seek a new host. In the aquarium, they reinfect the same fishes, and bore into the mucosa of the skin, gills, and fins of their hapless hosts. Once embedded in the tissue, they mature into typical trophonts, appearing as pinhead-sized white spots on most fish, and start the cycle of infection all over again (Basleer, 2000). It is these heavy infestations that can overwhelm even healthy fish.

The free-swimming stage of their life cycle is Cryptocaryon’s one great weakness. The motile tomites are vulnerable and exposed. Ozone or UV can destroy them, they can be killed by all the usual chemotherapeutic agents, and they explode (lyse) when exposed to freshwater and low salinity. It is therefore the tomites that the aquarist must target when treating Cryptocaryon.

At 100x magnification, Cryptocaryon parasites can easily be identified in skin and fin smears. They appear as large, dark, bell-shaped or conical organisms measuring about 350-400 micrometers in diameter (Basleer, 2000).

Outbreaks usually coincide with the introduction of new specimens or environmental insults such as rapid temperature fluctuations (heat stress or chilling), ammonia or nitrite spikes, or a sharp drop in pH (Basleer, 2000). The first step toward treating Cryptocaryon is therefore to restore water quality. Check your aquarium parameters and administer water changes as needed.

The traditional treatment is similar to that for Amyloodinium. Combination drugs such as formaldehyde/copper sulfate or formaldehyde/malachite green are often more effective than copper alone (Basleer, 2000). Medication must be maintained at therapeutic levels for at least 8-10 days and the best results are obtained when daily freshwater dips are a part of the treatment regimen (Basleer, 2000). The entire tank should be treated and methylene blue can be added to the water to aid the breathing of the fish (Basleer, 2000). Be aware that these medications will impair your biofilter and kill your invertebrates!

Cryptocaryon is normally easily distinguished from Amyloodinium by the fact that the embedded parasites produce pinhead sized white spots that are much larger that the tiny dust specks that indicate Marine Velvet. However, the telltale white spots are again often entirely absent when seahorses are the hosts, leaving the seahorse keeper in a quandary when it comes to diagnosis and treatment.

In your case, Seagazer, since you do not want to treat your tank with the usual copper-based medications, there are two other options for eradicating Cryptocaryon you can consider: (1) a two-week regimen of Parinox or (2) administering hyposalinity or Osmotic Shock Therapy (OST) at a specific gravity of 1.010 for a period of six weeks.

Since the hyposalinity could prolong the cycling process on a new aquarium, treating the 30-gallon aquarium with Parinox as described below may be a better choice:


USE: For Ich, hexamita, costia, ichthyophthirius, ectoparasites, monogenia, hirudinea, parasitic copepods, argulus, lernaea, anchor worms, fish lice, leeches. Also a protozoacide. Anti-bacterial, anti-parasitic, very wide spectrum.

DOSAGE: Use 1/4 teaspoon per 20 gallons. Treat once a week for 2 weeks. If water changes are done, add back the percentage of medication according to how much water was changed.

You can obtain Parinox online from National Fish Pharmaceuticals at the following URL:

Click here: Fish Medications

As you can see, the medication is effective against a broad range of ectoparasites and protozoan parasites, including saltwater ich (Cryptocaryon irritans). Although Parinox is safe for seahorses and damselfish, it can be hard on crustaceans and certain invertebrates. I don’t believe it will impair your biofiltration at all, so you can use it to treat the main tank and eradicate any parasites it may be harboring providing your tank does not include a lot of sensitive invertebrates, Seagazer. Ideally, it’s best to treat the main tank when there’s an outbreak of parasites to prevent reinfestation, so I would talk to fishyfarmacy over the phone and explain exactly what you have in your tank so they can determine whether or not Parinox would affect any of the other specimens. Tell them you are preparing a new aquarium and the damselfish you’re using to cycle it have developed saltwater ich and you want to use Parinox to eliminate the parasites, and then follow their recommendations. If they indicate that the Parinox would be hard on any of the sessile organisms growing on your live rock, then you could treat the tank with hyposalinity instead.

Let me know if you decide to use hyposalinity to curb this outbreak of Cryptocaryon, Seagazer, and I will provide you with complete instructions for administering osmotic shock therapy. There are number of precautions and provisos you must observe in order to use hyposalinity safely and effectively.

If you can catch the damselfish relatively easy, it would also be a good idea to administer a freshwater dip to them in order to provide them with immediate relief from any embedded trophonts they may be carrying.

Freshwater dips and baths are a form of osmotic shock therapy. The abrupt change in salinity when going from normal strength saltwater to freshwater causes water to move into the bodies of the parasites via osmosis until they rupture (lyse) or burst. Seahorses normally tolerate an 8-10 minute dip in freshwater very well, providing the dipping water has been pre-adjusted to the same temperature and pH as the aquarium, and a daily freshwater dip will provide the affected fish with immediate relief and hasten their recovery from this disease.

Freshwater Dip Instructions

A freshwater water 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).

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 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 experienced no problems, but if you see continued signs of distress — twitching, thrashing around etc. — stop the treatment.

There is an excellent new book about diseases in seahorses that you would find very informative, Seagazer. Dr. Martin Belli, Marc Lamont, Keith Gentry, and Clare Driscoll have done a terrific job putting together "Working Notes: A Guide to the Diseases of Seahorses." Hobbyists will find the detailed information it contains on seahorse anatomy, the latest disease diagnosis and treatment protocols, and quarantine procedures to be extremely useful and helpful. It has some excellent dissection and necropsy photos as well as a number of photos of seahorses with various health problems. This is one book every seahorse keeper should have in his or her fish-room medicine cabinet, and I highly recommend it! In time of need, it can be a real life saver for your seahorses. It’s available online at the following web site:

Click here: Working notes: a guide to seahorse diseases > books > The Shoppe at | CafePress

It’s wonderful that two of your adolescent seahorses from your first brood have developed elaborate dermal cirri — those are attractive adornments that always dress up a pony!

As you know, Seagazer, dermal cirri are fleshy tabs or branching outgrowths of the skin that serve to break up the seahorse’s outline and allow it blend into its weedy habitat all the better, a sort of natural camouflage. Unlike spines, cirri are not permanent structures in most cases. Up to a certain age at least, seahorses appear to be capable of growing or shedding these fleshy filaments as the occasion demands in order to better suit their surroundings. For example, specimens that are rafting in clumps of Sargassum are apt to have well-developed cirri, giving them an appropriately shaggy appearance, while a seahorse inhabiting the mudflats of an estuary will be smooth skinned. Cirri grow most commonly on the head and neck region and are more common in juveniles than adults.

The presence of cirri is a highly variable trait and some species never have them. They are very rare or nonexistent in many seahorses, while in other species they are relatively common. For example, Hippocampus comes and H. reidi are smooth-bodied seahorses that never seem to develop cirri (Giwojna, Oct. 2003). Consider them cue balls — the Kojaks of seahorses. On the other hand, Hippocampus guttulatus are famous for their cirri and many Pot-Bellies (H. abdominalis/H. bleekeri) also sport fancy headdresses (Giwojna, Oct. 2003).

But even in seahorses where cirri are not uncommon, such as Hippocampus zosterae and H. erectus, the occurrence of cirri varies greatly from individual to individual (Giwojna, Oct. 2003). Most dwarf seahorses have no cirri, but some of them are regular little fuzz balls. That’s the case with Hippocampus erectus as well. Most Mustangs and Sunbursts (H. erectus) lack these appendages altogether, some have just a few, and the individuals with really extravagant cirri are relatively rare (Giwojna, Oct. 2003).

It’s a shame seahorses with well-developed cirri aren’t more commonplace because they can be quite breathtaking. A heavy growth of cirri can transform an ordinary specimen into a real show horse, making them appear as if they were adorned with a fancy mane or wearing an Indian war bonnet. A seahorse with extravagant, well-developed cirri can indeed be very exotic looking, but sometimes it has the opposite effect, lending them a comical appearance instead (Giwojna, Oct. 2003). I’ve seen shaggy specimens that looked like they were having a bad hair day, sporting a Mohawk or spike hairdo (Giwojna, Oct. 2003). Voila — a punk-rock pony, going through its rebellious teenage phase! Either way, they dress up the seahorses and give them a little extra pizzazz, and that’s what makes seahorse keeping so much fun!

I agree with you entirely, Seagazer, that this particular hobby can sometimes become addictive. I know many seahorse keepers that have developed flat-nose syndrome from keeping their faces pressed up against their seahorse tanks so they don’t miss any of the action. Hobbyists who can’t quite tear themselves away from their tanks sometimes refer to their habit of seahorse-gazing as "watching the seahorse channel" because it’s by far their favorite show.

Best wishes with your prolific ponies and all their offspring, Seagazer! Here’s hoping you have no trouble ridding your tank of Cryptocaryonosis and cycling it for your juvenile seahorses.

Pete Giwojna

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