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“White-spot” Parasite, Ichthyophthirius multifiliis

This disease is easy to recognise, as the skin of the infected fish becomes covered with white spots, each the size of a pinhead. Each spot represents the site of one, or sometimes two, parasites. All parts of the body gills, may be attacked.

The causative agent is named Ichthyophthirius multifiliis. It is a spherical and large by protozoan standards, measuring up to 1mm in diameter. Short, hair-like processes known as cilia are spread densely over the surface. A horseshoe-shape nucleus is also present which is clearly visible under the microscope.

By the means of the cilia the parasite rotates vigorously and burrows into the surface layer (epidermis) of its host. It feeds on skin cells and surface debris. The burrowing action causes a local irritation and the epidermis grows across the parasite to enclose it, thus forming a “White Spot”

Reproduction occurs away from the host. After maturing in the skin, which takes a few days to three weeks, depending on the temperature, the parasite bores out, swims away and comes to rest on a submerged object such as a stone, or plant. Here it forms a jelly-like cyst within which a series of rapid cell divisions take place. In a few hours, several hundred daughter cells or swarmers, are produced, which break out of the cyst to find a new host. Alighting on the skin, they burrow in to recommence the life cycle. If they fail to find a host within three to four days, they perish.

Symptoms
If the protozoan is introduced into a tank containing healthy fish, little harm may occur, other than a fleeting infection with a few parasites. If however, the fishes are already weakened for some other reason, e.g. lack of oxygen, the parasite will quickly cover the whole body surface, causing irritation and opening up wounds for secondary infections. The host mobility may become affected. In sever cases, death may result.

Prevention
If white-spot appears in an otherwise healthy tank, the parasite “must” have been introduced either as an adult on a newly acquired fish, or as the cyst form on, for example new stones, a plant or even added water. The only certain method of prevention, is to quarantine all new stock, including stones, plants etc; preferably in water at a temperature of 77F. Allow one week’s quarantine.

Treatments
There are too many treatments today to recommend any specific one. Many can be bought easily at aquarium outlets.


Several very interesting points to think about.

Very easy to recognise.
Its reproduction cycle.
No host they will die.
If introduced into a healthy tank little harm may occur.
Pay attention to all tank details.
Weakened fish, and lack of oxygen can/may and will cause sever deaths. All this is usually caused by poor tank maintenance and/or incorrect and faulty equipment.
Prevention is the best cure
A Parasite “must” be introduced into the tank.

This information was collected from Fresh Water Tropical Fish


Keith

Last edited by keithgh at 28-May-2005 22:33

Last edited by keithgh at 02-Jul-2005 20:20

Last edited by keithgh at 08-Jul-2005 03:53

Last edited by keithgh at 09-Aug-2005 01:57

Last edited by keithgh at 19-Sep-2005 01:17

Near enough is not good enough, therefore good enough is not near enough, and only your best will do.
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My reason for posting this is to help the many members who are asking about this killer which is very easly preventable.

When I first started 35+ years ago I had many outbreaks and lost too many fish. The information was just not there to be found. Therefore you had to seek help from the local LFS, and if I remember correctly the advise was always buy this blue stuff and if it does not work add more and more. Naturally many fish died. Then you went and bought more.

The main points I think here are "Prevention" and it "must" be introduced either by a carrier or the in the water during a change. For prevention I always recommend preparing the water one week in advance and if the parasite is in the water it will die as it has no host to survive and reproduce.

Another very important fact is that you must have a healthy tank to have healthy fish.

To have a happier life for your fish and your self please consider all these facts.

Keith

Last edited by keithgh at 28-May-2005 22:30

Near enough is not good enough, therefore good enough is not near enough, and only your best will do.
I VOTE DO YOU if not WHY NOT?
VOTE NOW VOTE NOW

Plus, as you've said above Keith, knowing the life cycle of the parasite and when it's most vulnerable to medication is a key factor in successful elimination when it does strike.

All Ich meds now come with instructions to continue medicating for at least 72 hours after the cysts have all dropped off the fish. This is so that the meds can kill the free-swimming stage of the parasite, the only phase in the life cycle that is vulnerable to attack. Usually, it is recommended to combine this with temperature elevation to speed up the parasite's life cycle, and bring it to the point where it is free-swimming and vulnerable that much quicker. If there is a compelling reason not to raise the temperature (e.g., you have fish that will expire if the temperature is raised too high), then the medication period needs to be prolonged accordingly.


Panda Catfish fan and keeper/breeder since Christmas 2002

That and if i here one more person say it's contaigous, i'm going to put an axe through my monitor.

With Ich being such a problem for some I was supprised at the low responce to this informative article.

Keith

Near enough is not good enough, therefore good enough is not near enough, and only your best will do.
I VOTE DO YOU if not WHY NOT?
VOTE NOW VOTE NOW

thank you Keith for your very informative piece. My tank suffered Ich a few weeks ago, thankfully through the help and guidance from this website, I was able to get rid of it all with only one fish dying. It was caused by the drop in temp of the water - coming into winter apparently it is quite a common parasite to get at this time of year.

That and if i here one more person say it's contaigous, i'm going to put an axe through my monitor.

of course its contagious what are you on about? Its contagious in the same way fleas and head lice are contagious. I suppose you could call it transmittable, but contagious isn't wrong enough to warrant an axe, surely?

'flu is contagious, doesn't mean everyone who comes in contact with it shows signs or carries the disease.



transmittable? communicable? infectious?

any of those sound better?




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