Thanks for the update! It’s very unfortunate that your Brazilian seahorse that make it, but it’s great to hear that your little yellow erectus is responding well to the hyposalinity and has begun eating live brine shrimp aggressively.
The osmotic shock therapy will assure that you don’t have any further problems with marine ick (Cryptocaryon irritans) as long as you maintain the hyposalinity at the proper level. Because these parasites undergo a complicated life cycle and are only vulnerable in their brief free-swimming stage of existence, it’s important to maintain the hyposalinity for 6-8 weeks to assure that you have the eradicated all of the Cryptocaryon.
As you know, Cryptocaryon is commonly known as saltwater ich or white spot disease. It is caused by a ciliated 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Here is an excerpt from my new book (Complete Guide to the Greater Seahorses in the Aquarium, unpublished) that discusses the symptoms and treatment options for Cryptocaryon irritans in more detail:
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!
For this reason, hyposalinity or osmotic shock therapy (OST) is my preferred method for eradicating Cryptocaryon from a seahorse tank.
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. <Close quote>
That’s the rundown on Cryptocaryon irritans, FERS4REEF.
For best results, I recommend maintaining the hyposalinity for six to eight weeks to ensure that all of the encysted parasites have emerged and been killed by the osmotic shock therapy. After six to eight weeks, you can then very gradually return the aquarium to normal salinity over a period of about a week.
Your ultraviolet sterilizer can not cure an active infection of Cryptocaryon. But once the osmotic shock therapy has completely eliminated the Cryptocaryon from the aquarium, your ultraviolet sterilizer should help curtail future problems with Cryptocaryon.
Best of luck with your surviving H. erectus seahorse, FERS4REEF! He should be feeling a great deal better now that the Cryptocaryon is under control, and hopefully you’ll be able to wean them onto frozen Mysis as a staple diet soon.