WHITE SPOT AKA ICH ICHTHYOSPORIDIUM multifiliis (protozoan ciliate)

SYMPTOMS

Small, pure white, clearly-defined spots (about 1/4 - 1/2 dia..... of pinhead) appear on body AND finnage. (Do not confuse with same-sized GREYISH-WHITE, blurred-edge spots appearing on finnage only - see FLUKES). If untreated, spots slowly (6-24 hrs..) advance to cover whole body/fins. Fishes do not show same early sickliness as with Fungal Ich and may even continue feeding lightly. Eventually the fish become lethargic and apathetic. Then the spots appear larger and the skin begins to disintegrate, signifying the imminent death of the fish.

Diagnosis
Typical behaviours of clinically infected fish include:

Anorexia (loss of appetite, refusing all food, with consequential wasting)
Rapid breathing
Hiding abnormally/ not schooling
Resting on the bottom
Flashing
Rubbing and scratching against objects

A subclinically infected fish will not show any of these signs. For example, a healthy fish with a newly attached trophozoite will not yet have clinical disease. The trophozoite will not become visible to the naked eye until it has fed on the fish and grown to one or two millimetres. A trophozoite attached to the gills usually is not readily seen. A subclinically infected fish may initially only have a single trophozoite.

Visible Ich lesions are usually seen as one or several characteristic white spots on the body or fins of the fish. The white spots are single cells called trophozoites or trophonts, which feed on the tissues of the host and may grow to 1 mm in diameter. A smear should show ciliates if white spot is present.
Fins are folded and show white spots about 1 mm in diameter.
Eyes may appear cloudy or milky. Gill infection will cause breathing at the surface and fast respiration. Gill examination may show numbers of such white spots. Wet mount of a Gill Biopsy may show I. mutifiliis trophozoites.

DISEASE :

AKA:

Taxonomy.

DESCRIPTION/

MORPHOLOGY

The ciliate, Ichthyophthirius multifiliis, is an obligate parasite that affects all species of freshwater fish, causing the disease ichthyophthiriasis, which is commonly referred to as ich or white spot. I. multifiliis is one of the most prevalent protozoan parasites of fish and is an important pathogen of ornamental and farm-raised food fish species when reared under intensive conditions. Wild fish populations are also susceptible and outbreaks are occasionally seen. .. Highly dependent on water temperature, the entire life-cycle takes approximately 7 days at 25 °C (77 °F) to 8 weeks at 6 °C (43 °F). Marine ich is caused by a different ciliate, Cryptocaryon. Like other ciliates, I. multifiliis cells have a transcriptionally inactive germline micronucleus and a transcriptionally active somatic macronucleus.

LIFE CYCLE

Predisposing factors
There is no dormant stage in the lifecycle. Ich does not lie in wait for a weakened fish to infect. However, any factor that reduces immunity like changes in water temperature and quality may, in a subclinically infected fish, accelerate an outbreak of Ich. The presence of ammonia, nitrite and high levels of nitrate in water or poor water quality will stress fish, allow an outbreak to spread rapidly and increase mortality rates in infected fish.

The three phases of the ichthyophthirius life-cycle (Adult, Cyst, Free swimming) take about 4 weeks at 21 °C (70 °F) to complete but only 5 days at 27 °C (80 °F). For this reason it is recommended that the aquarium water be raised to 28-30 °C (82-86 °F) for the duration of the treatment. Avoid fast temperature changes; water temperature should be raised or reduced gradually 0.5-1 °C (1-2 °F) per day. There are species of fish that will not tolerate the high end of temperatures needed to be effective. If the fish can stand it, raise the temperature even higher, up to 30 °C (86 °F). Raising the temperature also, presumably, reduces and kills the free swimming parasite. It is important to remember that raising the temperature higher, but not high enough so that the parasite is killed, should be used in conjunction with some sort of medication. The heat speeds up the life cycle of the ichthyophthirius, which is useful if the fish is being medicated, because otherwise the parasites simply reproduce at a faster rate, and kill the fish quicker. Temperatures at or above 30 °C (86 °F) are generally considered to be fatal to ich[2]

IMAGE/S

KNOWN TREATMENT/S

Waterlife: PROTOZIN. NB: In very hardwater areas the PROTOZIN should be used twice daily in the early morning and late at night.

Only the free-swimming stage of the parasite is susceptible to treatment; neither the trophonts under the epithelium nor the tomont cysts can be killed.

Heat treatment can be highly effective, and it can be combined with other treatments.

In small tanks, a specific gravity of 1.002 g/cm³ as the parasites are less tolerant of salt than fish. Fish can be dipped in a 0.3% (3000 mg/L; pure water at 4 °C) solution for thirty seconds to several minutes, or they can be treated in a prolonged bath at a lower concentration (0.05% = 500 mg/L; pure water at 4 °C). Salt at low concentrations (0.01 to 0.05% solution) is an effective means of controlling "Ich" in recirculating systems without harming the biofilter. Care should be taken to avoid damaging aquatic plants and salt intolerant fish. In particular, do not use salt with sensitive soft water Tetras such as Neons, Cardinals and Glow-Lights or scaleless Catfish and Loaches (which can be easily burned if salt is not pre-dissolved).

Salt treatment can be combined with heat treatment. Untergasser recomends raising temperature to 28-30C for at least three weeks.

Formalin, Malachite green, Chelated copper, Copper sulfate, Potassium permanganate, Acriflavin(AKA Trypaflavin, Quinine Sulfate. All treatments target the free-living theronts and tomonts, which only survive about two to three days in the absence of a host fish, so treatment should be continued until a few days after the last white spot has disappeared from the fish. This will usually take about a week; 10 days is typical at 27 °C (80 °F) and 6 days at 29 °C (84 °F). Always increase aeration with an increase in heat.

All medications, to some degree, are toxic not only to the parasite but also to the fish. Grossly weakened fish will not tolerate medication that more robust and less infected ones may.

Gravel vacuuming is not effective in reducing parasite load.

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PREVENTION

Preventing the introduction of infected fish into the aquarium is the only way to avoid Ich. Infected fish may be either subclinically infected (showing no symptoms or white spots)or clinically infected. Preventative measures against Ich include buying only healthy fish from reputable dealers; using quarantine and treatment procedures for ALL new fish before their introduction to the main group; preventing introduction of tomites/theronts on plants and hardware like nets, filters and pumps. Newly acquired, subclinically infected fish introduced to a tank or pond without quarantine and is the most common cause of Ich outbreaks.

Prognosis
When Ich is diagnosed early, effective treatment is used and stresses are minimised, mortality rates can be low. However if the infection is at an advanced stage,treatment protocols not followed and the fish are stressed, higher death rates will occur. When a fish has had Ich eradicated, it may develop partial resistance to reinfection. Partially treated fish may initially harbour low numbers of unseen trophozoites, often in the gills. This subclinical carrier will cause another outbreak weeks later, especially when for example stresses occur or uninfected fish are introduced to the aquarium.

References