Cryptocaryosis (Cryptocaryon irritans) in Fish

A genus of tropical and subtropical trees called Cryptocarya spp. is responsible for the fungus infection known as cryptocaryosis.

Most immunocompromised people are affected by it, and it can result in a variety of clinical symptoms, such as respiratory failure and organ failure. Although having a name that sounds similar, the parasite Cryptocaryon irritans is not related to Cryptocarya species of fish.

Agent of causation in cryptocaryosis

Cryptocarya spp., a genus of tropical and subtropical trees, are responsible for cryptocaryosis. Although the precise method of Cryptocaryosis transmission is unknown, it is thought to involve inhaling Cryptocarya spp. spores or conidia.

Cryptocaryon irritans morphology

While Cryptocaryosis and Cryptocaryon irritans are unrelated, the parasite of marine fish has a similar name. It is a ciliate with an extended oval form, which it uses for locomotion and feeding.

A parasitic ciliate that affects marine fish is called Cryptocaryon irritans, often known as marine ich or white spot illness. The following is a description of Cryptocaryon irritans’ morphology:

Shape: The ciliate Cryptocaryon irritans has an oval form and measures about 0.2–0.3 mm in length.

Color: The ciliate is transparent, but due to the host’s skin color coming through, it may appear slightly yellow or brown.

Cilia: The entire body of Cryptocaryon irritans is covered in rows of cilia that resemble hair. Both mobility and feeding are facilitated by these cilia.

Suctorial disc: Cryptocaryon irritans attaches to its host’s skin using a large, disk-shaped structure on the bottom. The suctorial disc is a structure that’s employed for mating and eating.

Single nucleus: The body of Cryptocaryon irritans has a single nucleus that is situated in the middle.

Large vacuoles are present in the ciliate and are used for both storage and excretion.

Life cycle Cryptocaryon irritans

Life cycle of Cryptocaryon irritans
Figure: Life cycle of Cryptocaryon irritans; Source: UF IFAS Extension

Cryptocaryon irritans goes through six stages in its life cycle: the trophont, protomont, tomont, theront, protomont, and tomont.

It causes a variety of clinical signs and symptoms in fish by attaching to their skin and gills.

There are multiple stages in the life cycle of the marine ich Cryptocaryon irritans:

Trophont stage: The parasite’s life cycle starts with the trophont stage, which is a feeding stage that attaches to a fish’s skin, fins, or gills. It latches on and starts consuming the fish’s blood and tissues.

Tomont stage: The trophont enters the tomont stage when it separates from the fish after many days of feeding and sinks to the aquarium’s bottom, where it encysts. The tomont is a stage that is quiescent and is encased in a protective cyst.

Theront stage: The tomont, the parasite’s infectious stage, splits into hundreds of small theronts after a number of days. Swimming freely in the water, the theronts look for a host fish to infect.

The trophont stage (re-infection) is when a theront attaches to a host fish and starts eating, beginning a fresh cycle of infection.

Depending on the water’s temperature and other environmental circumstances, Cryptocaryon irritans’ life cycle can be finished in as little as 6-7 days.

Due to the parasite’s quick life cycle, it is crucial for fish keepers to take precautions and treat any affected fish right once in order to stop the disease from spreading to other species in the aquarium.

Cryptocaryon irritans’s geographic range

Globally, tropical and subtropical marine settings are home to Cryptocaryon irritans, with the Indo-Pacific area reporting the highest occurrence.

A widely dispersed parasite called Cryptocaryon irritans can be found in different maritime settings all around the world.

Although it can be found in temperate waters, it is most frequently seen in tropical and subtropical areas.

Geographical areas it covers include: From the Gulf of Mexico to the Caribbean Sea, including the shores of Florida, the Bahamas, and the Lesser Antilles, Cryptocaryon irritans is present in the western Atlantic Ocean.

Eastern Atlantic Ocean: From Mauritania to South Africa, it can also be found on the African continent’s coastlines.

Indo-Pacific region: Cryptocaryon irritans is frequently found along the coasts of Southeast Asia, Australia, and the Pacific islands in the Red Sea, the Indian Ocean, and the Pacific Ocean.

Mediterranean Sea: It has been reported that Cryptocaryon irritans has entered the Mediterranean Sea, perhaps as a result of shipping and aquaculture operations.

Fish species affected by Cryptocaryon irritans

Cryptocaryon irritans infects a range of marine fish species, including but not limited to: clownfish, tangs, damsels, and wrasses.

A parasitic ciliate called Cryptocaryon irritans can harm many different types of marine fish.

But certain species are more prone to illness than others. The following fish species are some examples of those that Cryptocaryon irritans frequently harms

A parasitic ciliate called Cryptocaryon irritans, often known as marine ich or white spot illness, affects a variety of marine fish species. Cryptocaryon irritans frequently affects a number of fish species, including:

  • Tangs for clownfish (surgeonfish)
  • Angelfish
  • Gobies
  • Wrasses
  • Damselfish\Chromis\Blennies
  • Triggerfish\Pufferfish

These are only a few instances of the numerous marine fish species that Cryptocaryon irritans can infect.

Owners of fish should take precautions to reduce the chance of infection as well as learn the signs of the illness and seek treatment right away if they do contract it.

Causing sign and symptoms

A variety of clinical signs and symptoms, including but not limited to: white spots on skin and fins, rapid breathing, clamped fins, and loss of appetite, can result from Cryptocaryon irritans infection in fish.

Fish afflicted with Cryptocaryon irritans, often known as marine ich or white spot disease, can exhibit a wide range of signs and symptoms. They may consist of:

White spots: that form on the fish’s skin, fins, and gills are the disease’s most obvious symptom. These spots, which are visible with the naked eye, are brought on by the parasite’s existence.

Scratching: Sick fish may scratch the substrate or other aquarium fixtures in an effort to feel better. The fish may suffer skin and fin damage as a result, which increases their vulnerability to secondary illnesses.

Respiratory distress: Fish gill infections by Cryptocaryon irritans can also result in respiratory distress. Fish with the infection may gasp for breath at the water’s surface or show fast gill movement.

Fish with the infection may exhibit altered behavior, such as becoming lethargic or losing their appetite, as well as isolating themselves from other fish in the tank.

Secondary infections: If Cryptocaryon irritans is not treated, affected fish may become more vulnerable to subsequent bacterial or fungal diseases due to a weakened immune system.

Diagnosis of Cryptocaryosis

The diagnosis of Cryptocaryosis is based on a combination of clinical, radiological, and laboratory findings.

Chest radiographs and computed tomography (CT) scans may show pulmonary infiltrates and pleural effusions.

Laboratory tests, such as sputum or blood cultures, may also be performed to confirm the diagnosis.

Based on the signs and symptoms displayed by the fish, marine ich, or Cryptocaryon irritans infection, can be diagnosed. A distinguishing feature of the illness is the appearance of tiny, white spots on the skin, fins, and gills.

A veterinarian or fish health expert may do a skin scrape or fin biopsy to look for the parasite under a microscope in order to confirm the diagnosis.

With a sterile blade or scalpel, the scrape or biopsy can be extracted from the afflicted area of skin or fin.

A fish may harbor the Cryptocaryon irritans infection in some instances without displaying any outward symptoms of the illness.

In these circumstances, a veterinarian may carry out a more thorough examination to search for additional indications of infection, such as behavioral abnormalities or respiratory problems.

If fish owners believe their fish may be suffering from Cryptocaryon irritans or another illness, they should consult a veterinarian or fish health expert.

The likelihood of a favorable outcome can be increased and the sickness from infecting other aquarium fish can be stopped with prompt identification and treatment.

Prevention of Cryptocaryosis

Given that the precise mode of transmission is unknown, prevention of cryptocaryosis is difficult.

Immunocompromised individuals should avoid exposure to Cryptocarya spp. trees and take appropriate precautions when in environments where they may be present

Fish keepers can take the following measures to help avoid marine ich, also known as Cryptocaryon irritans infection, in their aquariums:

Fresh fish should be quarantined for at least 4-6 weeks in a separate tank before being introduced to the main aquarium.

Before the fish are transferred to the main tank, this gives time for any potential parasites or diseases to be discovered and treated.

Keep good water quality since stressed or immunocompromised fish are more susceptible to infection by Cryptocaryon irritans.

Regular water changes and suitable filtration can assist maintain good water quality, which can lessen stress on fish and promote their health.

Avoid overstocking the aquarium because it can cause stress in the fish and weaken their immune systems, making them more prone to infection.

Utilize a quarantine tank for sick fish: To stop the disease from spreading to other fish, sick fish in the main aquarium should be evacuated and treated in a separate quarantine tank.

To prevent equipment sharing, each aquarium should have its own nets, siphons, and other accessories. By doing this, illness transmission between aquariums may be reduced.

By adopting these actions, fish owners can lessen the chance that their fish will become infected with Cryptocaryon irritans and foster their general well-being.

Treatment of Cryptocaryosis

Treatment options for Cryptocaryosis are limited, and there is no standard protocol. Antifungal medications, such as amphotericin B and voriconazole, may be used to treat the infection.

There are many drugs that are sold over-the-counter or through a veterinarian that can be used to treat the infection known as marine ich or Cryptocaryon irritans.

To stop further infection and spread, the purpose of treatment is to get rid of the parasite from the fish and the aquarium.

Medication containing copper: Copper is a popular and efficient treatment for Cryptocaryon irritans.

Copper-based drugs should be used cautiously and in accordance with the directions on the label because, if misused, they can be hazardous to fish and other aquarium inhabitants.

Medication based on formalin: Another drug that has the potential to be beneficial in treating Cryptocaryon irritans is formalin. Although it is less toxic than drugs based on copper, improper use can still be detrimental to fish and other aquarium occupants.

Saltwater baths or dips: Saltwater baths or dips can be used to treat Cryptocaryon irritans. A saltwater solution intended to kill the parasite is briefly poured over the fish. The fish may experience stress from this procedure, thus it should only be handled with care.

UV sterilization: UV sterilizers can be used to kill Cryptocaryon irritans in the water as a preventative measure or in conjunction with medication.

Any medication should be taken exactly as directed, and the fish should be thoroughly watched both before and after therapy. Diseased fish that are weak or stressed may be more vulnerable to

Maintaining adequate water quality and reducing stress on the fish during treatment and recovery are crucial to prevent subsequent infections.

It’s crucial to keep in mind that treating Cryptocaryon irritans can take a few weeks, and it’s crucial to keep up medication until the parasite has been totally eradicated.