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Marine Ich (Cryptocaryon irritans) - Updated 1-20-23
What You Need To Know:
* Fish parasite which is sometimes managed in a DT by utilizing a UV Sterilizer, Ozone, Diatom Filter, Oxydator, herbal remedies, enhanced nutrition, etc. etc.
* Can be treated in a quarantine tank by using Hyposalinity, Chloroquine, Copper or Tank Transfer Method.
* The fallow (fishless) period for starving ich out of a Display Tank is 6 weeks IF aquarium temperature can be raised to 27C/80.6F.
* Primary symptom is salt or sugar-like “sprinkles” on the body & fins (see photos below):
Understanding Marine Ich
Unlike most other diseases, Marine Ich (Cryptocaryon irritans) has been well studied and documented due to its prevalence and threat to the aquaculture industry. The life cycle of this parasite is well understood, and treatment options have been thoroughly tested. The information found below provides a basic understanding of ich, it's life cycle and treatment options.
Terminology – The following terms are used to describe the various stages of ich’s life cycle:
* Trophont: The “feeding stage” of the parasite that attaches itself to the fish, commonly associated with salt or sugar-like “sprinkles” on the body and/or fins. These sprinkles are not the actual parasite, but are the fish’s immune response to the parasite. Each white dot is caused by excess mucous which forms around the area where a trophont latches onto the fish. Ich trophonts burrow in under the epithelium (outer skin layer), are oval shaped, and range in size from 48 x 27 to 452 x 360 micrometers. White spots are not always visible when a fish is infected with ich, as the gills (which are out of sight) are easier for trophonts to penetrate. Trophonts in the gills cause excess fluid to build up, making it more difficult for the fish to breathe.
* Protomont: The life stage after a trophont drops off the fish, before becoming a tomont. Protomonts crawl around looking for hard surfaces to encyst upon.
* Tomont: The “encysted stage” which adheres to rocks, shells, substrate, glass – any hard surface really. This includes some corals/inverts. Tomonts produce “daughter” tomites, which are then released into the water column as theronts.
* Theront: The “free swimming” stage which seeks out fish to infect. Theronts are the only life stage susceptible to chemicals (e.g. copper) and hyposalinity. It is also possible to cross contaminate with theronts by sharing water between tanks or via aerosol transmission. Once a theront finds a fish and attaches, it becomes a trophont and the life cycle begins anew. (This can continue almost indefinitely without treatment in a QT & going fallow in the DT.)
Life Cycle – Marine Ich is most often introduced into an aquarium by a fish infected with trophonts. However, cross contamination or tomonts on corals/inverts are other possibilities. Assuming you are dealing with a fish carrying trophonts, this is how the life cycle plays out:
Credit: Charles Raabe
^^ As you may have noticed from the chart above, the timing for each stage to “move forward” to the next varies considerably. Therefore, ich is rarely in sync. For example, it is not unusual for a fish to be battling trophonts, while simultaneously theronts are swimming around looking for a host to feed on. This is especially true if your tank is plagued by more than one strain of ich. It’s this “perfect storm” that sometimes allows ich to overwhelm a fish's immune system and the fish dies.
Marine Ich (Cryptocaryon irritans) is best described as salt or sugar-like “sprinkles” on the body or fins. Sometimes however, the parasite can harbor inside the gills – out of sight. Behavioral symptoms such as flashing, scratching, twitching and heavy breathing are other possible indicators of ich.
Most hobbyists will encounter ich at some point in one of two settings:
More info regarding Marine Ich can be found in the links & video below:
edis.ifas.ufl.edu
ATJ's Marine Aquarium Site - Reference - Marine "Ich"
What You Need To Know:
* Fish parasite which is sometimes managed in a DT by utilizing a UV Sterilizer, Ozone, Diatom Filter, Oxydator, herbal remedies, enhanced nutrition, etc. etc.
* Can be treated in a quarantine tank by using Hyposalinity, Chloroquine, Copper or Tank Transfer Method.
* The fallow (fishless) period for starving ich out of a Display Tank is 6 weeks IF aquarium temperature can be raised to 27C/80.6F.
* Primary symptom is salt or sugar-like “sprinkles” on the body & fins (see photos below):
Understanding Marine Ich
Unlike most other diseases, Marine Ich (Cryptocaryon irritans) has been well studied and documented due to its prevalence and threat to the aquaculture industry. The life cycle of this parasite is well understood, and treatment options have been thoroughly tested. The information found below provides a basic understanding of ich, it's life cycle and treatment options.
Terminology – The following terms are used to describe the various stages of ich’s life cycle:
* Trophont: The “feeding stage” of the parasite that attaches itself to the fish, commonly associated with salt or sugar-like “sprinkles” on the body and/or fins. These sprinkles are not the actual parasite, but are the fish’s immune response to the parasite. Each white dot is caused by excess mucous which forms around the area where a trophont latches onto the fish. Ich trophonts burrow in under the epithelium (outer skin layer), are oval shaped, and range in size from 48 x 27 to 452 x 360 micrometers. White spots are not always visible when a fish is infected with ich, as the gills (which are out of sight) are easier for trophonts to penetrate. Trophonts in the gills cause excess fluid to build up, making it more difficult for the fish to breathe.
* Protomont: The life stage after a trophont drops off the fish, before becoming a tomont. Protomonts crawl around looking for hard surfaces to encyst upon.
* Tomont: The “encysted stage” which adheres to rocks, shells, substrate, glass – any hard surface really. This includes some corals/inverts. Tomonts produce “daughter” tomites, which are then released into the water column as theronts.
* Theront: The “free swimming” stage which seeks out fish to infect. Theronts are the only life stage susceptible to chemicals (e.g. copper) and hyposalinity. It is also possible to cross contaminate with theronts by sharing water between tanks or via aerosol transmission. Once a theront finds a fish and attaches, it becomes a trophont and the life cycle begins anew. (This can continue almost indefinitely without treatment in a QT & going fallow in the DT.)
Life Cycle – Marine Ich is most often introduced into an aquarium by a fish infected with trophonts. However, cross contamination or tomonts on corals/inverts are other possibilities. Assuming you are dealing with a fish carrying trophonts, this is how the life cycle plays out:
Credit: Charles Raabe
- A trophont will typically spend 3-7 days feeding on a fish, before dropping off to become a protomont.
- The protomont crawls around for 2-18 hours, looking for a surface to encyst upon. Once it finds this, it sticks to the surface, and begins the encysting process. The parasite is now called a tomont.
- It takes about 8-12 hours for the cyst to harden around the tomont. After this, the tomont goes into “reproductive mode” producing numerous daughter tomites. These tomites are then released into the water column as free swimmers or theronts. How long it takes for theronts to be released varies but is usually dependent upon water temperature. At 30C/86F it typically occurs within a week; 27C/80.6F is usually 2 weeks, although in at least one study it took up to 35 days at this temp. In a coldwater study @ 20C/68F (Colorni and Burgess 1997), it took 72 days for all the theronts to be released from a group of tomonts.
- The now “free swimming” theronts seek out fish to feed on, thereby becoming trophonts, and the cycle starts all over again. A given strain will die out after 100 generations or so. Given the average life cycle of ich is 2 weeks, this could take almost 4 years (on average).
^^ As you may have noticed from the chart above, the timing for each stage to “move forward” to the next varies considerably. Therefore, ich is rarely in sync. For example, it is not unusual for a fish to be battling trophonts, while simultaneously theronts are swimming around looking for a host to feed on. This is especially true if your tank is plagued by more than one strain of ich. It’s this “perfect storm” that sometimes allows ich to overwhelm a fish's immune system and the fish dies.
Treating Marine Ich
Marine Ich (Cryptocaryon irritans) is best described as salt or sugar-like “sprinkles” on the body or fins. Sometimes however, the parasite can harbor inside the gills – out of sight. Behavioral symptoms such as flashing, scratching, twitching and heavy breathing are other possible indicators of ich.
Most hobbyists will encounter ich at some point in one of two settings:
- A newly acquired fish in a quarantine tank (QT) – proceed to “Treatment options” below.
- Fish in the display tank (DT) – There is no easy way of dealing with this. Most corals/inverts are intolerant of chemical treatments (e.g. copper, chloroquine) or hyposalinity. Even in fish only systems, it can be problematic trying to treat in a DT environment. Copper (and other medications) can be absorbed by rock, and doing hyposalinity risks possibly wiping out your biofilter. Your best option is to catch ALL of your fish, and quarantine using one of the treatment options listed below. The DT itself should be left fallow (fishless) for 6 weeks @ 80.6F to starve out any remaining parasites.
More info regarding Marine Ich can be found in the links & video below:
FA164/FA164: Cryptocaryon irritans Infections (Marine White Spot Disease) in Fish
University of Florida, Institute of Food and Agricultural Sciences Extension outreach is a partnership between state, federal, and county governments to provide scientific knowledge and expertise to the public. The University of Florida (UF), together with Florida A&M University (FAMU)...
ATJ's Marine Aquarium Site - Reference - Marine "Ich"
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