This was written by a friend of mine he has bee nin this hobby for many years please read as there is a abundunce of information in this


Cryptocaryon irritans is a big problem in the marine ornamental fish hobby. It is so pervasive that it is really a matter of when you will have to deal with it and not so much "if" anymore. When I started the hobby back in the mid 80's it was not near the problem it is today. I cannot really account for why that is, but my supposition is that far less fish were being moved thru the custody chain and better specimens were being collected plus there were fewer vendors so the quality control may have been better....but I have no proof of any of it, just my opinion. I remember driving to Atlanta with my boss to pick out our fish and then drive them back to our store near Augusta. It was so much fun and mind blowing to see all those fish. Plus, being a poor minimum wage high school worker, I got to buy stuff at direct cost...great times. I have seen crypt on many fish in every store in the HR area.....and other areas. Many think that if they go to a LFS and see infected fish, that it is the store's fault.....some truth to that in a few cases....but it is not all their fault. Others think that if they go to a LFS and the operators are real nice, helpful and invigorating that their fish will also be the same way and that their attitude equates to healthy fish.....and that just isn't so either. Truth is anyone can experience crypt if they do not understand how NOT to experience it....at least in their display tank. Many times the problems begin well before the LFS owner placed his/her order for the fish in question. The way fish are collected and transported, it is quite easy to see how this parasite gets in to our tanks when the appropriate precautions are not undertaken. But there is great hope and cause for cheers, as it is something that we all can avoid. I refer you to the Quarantine thread.

Crypt is a protozoan parasite that many call "ich".....a leftover term for it's freshwater cousin Ichthyopthirius multifiliis. Many just kept the name because its appearance on fish is similar in presentation in both environments and they were already familiar with it. Actually though, it is more correctly referred to as crypt. This parasite has a specific and definite lifecycle. Knowledge of this lifecycle is paramount to understand how to get rid of it. It is nearly impossible to get rid of in a fully stocked reef tank that has fish in it.....at least in my experience and the experience of other aquarists whose knowledge and experiences I trust. I cannot stress enough that this parasite is an actual parasite...like fleas on a dog. It is not "caused" by temperature, poor nutrition, or an assundry of other causes. I even heard someone in one of the LFS say that "all bony fish have it and that stress just brings it out". There is an element to all of those statements, but to say that fish cannot be completely cured of the parasite and it cannot be totally eradicated from a system is just wrong....it just is. One can have a system where no matter what kind of stress a fish suffers, it will never break out with crypt....because they can create an environment where the parasite is just not present. Again, the key to this is to understand the lifecycle.

Some fish are able to live with the parasite and not die. If one visits Reef Chief and looks at the fish in the 210 as you walk in, there are a few fish in there that exhibit the parasite every week or so....especially the Powder Blue. <Edit> RC has since moved and that fish did eventually perish but lived in the system with the parasite for several months. Some fish manage to not die from this parasite, but that is the exception and not the rule. Sometimes aquarists are able to provide great nutrition and a stable system so that the fish find a tentative balance between their immune function and the parasites invasiveness. Facts are though that crypt is probably the single biggest reason that hobbyists lose fish in a "cycled" aquarium. It usually weakens and stresses the fish to the point that they perish after 2 or three life cycles of the parasite. The parasite just reaches such numbers that it overwhelms even healthy fish.

Crypt is a obligate fish parasite. It cannot live without a fish host during it's growth portion of the life cycle. I will start explaining the lifecycle from the attachment to the fish host since that is how nearly everyone will bring it into their aquarium. When the parasite is attached to the fish it is termed the trophont stage. This is the stage where they feed and grow to the salt size particles that you can see with your eyes. When they attach initially you cannot see them...they are too small....that is how you are able to bring home an infected fish and not know it for a week or two. The trophonts borrow under the mucus layer of the fish to mature/feed/grow before they leave the host over the course of a few days...of course all these timeframes are temperature dependent. Higher the temp, the faster the process. Do not believe the forum gurus that tell you temperature does not matter. This info I give you is based on the research done by Colorni and Burgess. For some reason there is a guy on Reef Central that has done no research but fancies himself a fancy statistician that is telling people that temp doesn't matter. Anyway.....at the point they leave the fish they are called protomonts.

Protomonts fall to the substrate and release their cilia...usually at dawn or dusk....and there is a sinister reason for this. Once detached they inch along the bottom until they find a suitable attachment point on some form of calcareous material. Once attached they form a cyst and become tomonts. This occurs over the course of a day usually.

Tomonts are the stage where the parasite undergoes rapid fission and produces the doom that is to come. The tomont rapidly undergoes binary fission to produce a couple hundred new ciliated parasites.....per tomont. This process can take several days or just a few....it depends on the temperature. In any event, once the process is complete the cyst will rupture and release these "babies" to seek out a host to start the process all over. Oh, and this release usually occurs at dawn or dusk....so that hopefully the fish is just sitting right there where it tends to go at night......told you it was sinister. The released babies are called theronts. They look like our childhood drawings of the sun....heck they look like my adult drawings of the sun..LOL...and they have anywhere from 12-24 hours to find a host or their high metabolism gets the best of them and they die.

Theronts attach wherever they can but if too many attach to the gill lamellae, it really poses a threat to the fish. Not only does it interfere with gas exchange, but it can severely limit the fish's ability to excrete waste and excess salt....adding to the stress.

Brooklynella and oodinium have similar lifecycles...except Brooklynella can leave one fish and infect another and both tend preferentially attach to the gills....and that is why they kill so fast. The gill lamellae are so important for much more than respiration. They also play an enormous role in Na+ and Cl- balance.....not to mention NH3+ excretion. Much of this stuff has to be done against a gradient already so that energy must be expended....and with few surface area if the parasites are attached. This causes the fish to retain higher levels of ammonia in the face of severe stress and an even greater oxygen demand. This is what leads to so many fish perishing.

There are many treatments that are offered for killing crypt. There are also a host of "reef safe" methods that are reported by a few as effective, but that is not my experience.....or the experience of most in general. The general concensus on "why" these methods have bouts of success is that the fish were healthy enough and the parasite weak enough that some immunity was found to allow the fish to overcome the parasite. The analogy I use when discussing this with some, is that Magic Johnson and several others have contracted HIV and not contracted AIDS. Does that mean the majority of people who have contracted HIV have not died within 5 years.....short answer is NO! In any event, crypt is a killer.....even with the best nutrition and fish crack in the world. Just because some people have encountered a great deal of luck and not had to tear down their whole reef to cure the fish, certainly does not mean that most will have that same luck. So I caution anyone who is using a "reef safe" method to treat crypt out of anything other than absolute necessity.

It is also important to note, that the research bears out that the only real vulnerable time to kill the parasite is in the theront stage. The tomonts are protected in their cyst and the theronts are largely protected by the mucus layer of the fish. This fact is why I mentioned why understanding the lifecycle is important. Many aquarists see their fish infected, add some garlic or "reef safe" med....or even a proven med....and see the spots go away and figure the fish is cured.....only to have the cysts rupture several days later and experience as even worse infestation. The research that supports the claims about the lifecycle and the parasites' vulnerability comes from reading articles published in the mariculture food industry literature. They have performed several research studies on the parasite and we have benefitted in the aquarium hobby as a result.

Copper is still considered the gold standard to treat crypt and oodinium (aka velvet). It is useless against Brooklynella. It must also be stressed to use an ionic copper medication. My personal favorites are the Red Sea copper (it also comes with the test kit) and Sea Cure by Aquarium Systems (it tests accurately with the Red Sea kit too). It is important though to try and ensure that the test kit you have and the copper you are dosing go together. Mainly, that the test kit will accurately register the type of copper you are dosing. I personally had poor results with Salifert's copper test kit and no longer will use it. The SeaChem kit requires an artist mind to differentiate the shades of blue you have to determine to read your copper level, so I cannot use that one either. Copper has a narrow therapeutic range so you will need to test frequently to keep the dose between too low to kill the parasite and too high to kill the fish. I personally run my copper level at 0.2-0.3 ppm for 3 weeks with the temp at 80F. I then do a series of 50% water changes over 3-4 days and wait another 3 weeks to ensure that the fish has no more outbreaks. If they break out again. I redose but this time shoot for 0.4 ppm. I have never had any parasite make it out of that dose. I did however lose 1 Powder Blue at that dose and that is why I no longer go straight to that anymore. As a note on chelated or aminated (cupramine)......I would keep a therapeutic level with these for a minimum of a month and keep a higher level 0.5-0.7 ppm. I no longer will use them because I find them to be less effective.....but that is just me. They are less reactive, easier on the fish, but also easier on the parasites at the lower doses I recommend for ionic copper. EDIT: I now use Cupramine. It is much gentler and safer. It has a larger therapeutic range and even with centropyge angels......has showed few problems with the several fish I have now treated or helped treat with it. I highly recommend using the SeaChem copper test kit along with it. Red Sea is still a good choice as used above, but because of the safety of Cupramine and its effectiveness......I recommend it over Red Sea to those not completely comfortable with copper treatment.

Hyposalinity has gained a lot of popularity and I myself have used it successfully....just recently too. It is recommended to keep the salinity level at 1.008-1.009 or 11 or 12 ppt. I keep the tank at that level for 4 weeks with the temp at 82-84 F. The theory on exactly how hypo kills the theronts is not exactly known. It is suspected that it renders the theronts unable to swim and they die from lack of finding a host. Hypo does not cause the cysts to rupture with enough certainty to kill all the parasites. Whenever I tried to cut the timeframe shorter than 4 weeks I had reinfestations. The Powder Blue in my tank at Sean's house and pictured in the photos he posted, spent 5 months in QT as a result of reinfestation because I tried to cut it short. I cured it of crypt with hypo too. Others may have had shorter times, but I could not get the results I needed with less than 4 weeks. A note on the high temps I am recommending.....the lower spg water will hold nearly the same O2 content at those temps as the NSW spg would at 78F, and it helps speed up the lifecycle of the parasite and also speeds up the metabolism of the theronts so they have less time to find a host. Good all the way around.

There is substance called methylene blue that I am able to procure thru the hospital, but you would need to find a source for it. I believe that Fish Pharmacy sells it in a huge lot and Kordon may have started making it available...that would need some investigating to be sure. Use of the 10% solution added until the water is a deep blue is recommended. Dip for 30-45 minutes (or as long as the fish is tolerating it). No need for aeration as the MB actually increases the O2 level the water can hold. I would never rely on this as a definitive measure though, only a step to use before placing the fish into the QT......and hope that no parasites made it thru and possibly help avoid further medication treatment in the QT period.

Formalin...which is 37% formaldehyde and malachite green can also be used effectively but are so hard to control without killing the fish, that they are seldom used anymore. Formalin is carcinogenic to both you and the fish so use caution when handling....but it is however the best treatment for Brooklynella.....if you recognize it in time to help. If someone wants to use these meds, PM me and I will help you as I can. I have used both successfully in the past. I used to really like formalin until I cured a Flame Angel only to have it die of a large head mass 4 months after the treatment.

Hope this all helps. Crypt is a royal PITB and something that you really want to prevent getting into your reef. It alone is enough of a reason to establish a QT tank.

Best wishes to you and your fishes.