Ich
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[edit] Alternative names
Ick, Ich, White Spot, White Point Disease.
The parasite species is named Ichthyophthirius multifiliis.
[edit] Occurrence
This parasite is very common.
[edit] Identifying
Tiny random scattering of white spots on the surface of the skin or gills of fish, resembling grains of salt.
[edit] Description
This parasite goes through several life cycles and it is only when the parasite transforms into the free swimming cyst stage can it reproduce and infect other fish.
Ich when in the free swimming 'cyst' stage need to find a host fish within 55 hours or it dies. When it finds a fish (usually through the gills) it lives in the host for about 5 days @ 25C* and can be seen as white spots as it ruptures through the skin. It then drops off and sinks to the substrate where each parasite developes into around 1000 more cysts which in turn swim looking for a host fish again.
* This time scale is dependant on the water temperature, lower temperture = more time at this stage.
[edit] Infectious
Very. Passes rapidly to other fish via water.
[edit] Treatment
Several methods work.
[edit] Heat Treatment
- 1. Raise temperature of water slowly over a day to 30°C (86°F) and leave for a week.
- When the parasite leaves the host in search of a new host, it will be killed by the water's temperature. With this treatment the cyst is killed during free swimming stage, this will not kill already attached parasites.
- 2. Continue treatment for at least 3 days after the last spot has disappeared to ensure complete elimination. Optionaly add an external antibacterial agent to stop wounds caused by the Ich from being infected. Slowly reduce the water temperature over a day back to the fish's normal temperature.
Advantages
- No chemicals required
- Cheap
- Always works
Disadvantages
- Stresses fish not used to high temperature.
- Some plants will not like the high temperature.
- Lowers oxygen content in water so a tank loaded with lots of fish may causes oxygen starvation. :*Extra aeration is advised.
[edit] Chemical Treatment
This parasite is so common that virtually all Pet shops sell a White Spot or Ich cure. These use chemicals to kill the creature when it's in the cyst stage. Therefore you have to constantly add the chemical every day for at least 8-14 days. The chemicals are typically formalin and malachite green. Both are toxic if exposed to fish in high dosages.
Advantages
- Allows fish and plants to remain at a safe temperature.
Disadvantages
- Cost money.
- Needs to be correctly dosed. Too little and it doesn't work. Too much and you harm the fish.
- You need to remove any Active Carbon filtering material from your tank as the carbon removes chemicals from the tank, possibly before they have been effective.
- You need to lower light levels as malachite green is photosensitive.
- Stresses scale-less fish like Clown Loaches, all species of corydoras, and many Plecos.
- Can potentially kill many invertebrates in both fresh and salt water.
[edit] After initial treatment
After either treatment method your fish will be wounded by the holes left by the Ich and the stress from heat or the chemical used and this can cause death. To prevent secondary infection by bacteria it is recommended to keep the water quality up by performing regular water tests and replacing 25% of the water if necessary for 2 weeks afterwards as this will reduce the bacteria and if you wish you can add any typical fish wound treatment commercial treatment sold.
[edit] Special Notes
1. Some people state that it only appears when the fish is stressed. Therefore suggesting that this creature suddenly appears from a dormant state. Whilst a previously infected fish can develop a form of immunity against it, the fact is that a single creature of Ich rapidly reproduces into 1000 within a few days.
2. Ich is only transmitted by water. It can not be transfered by air. Though it could be transfered by the Aquarist from one tank to another via water drips on hands or equipment. It is often transfered from pet shops via new plants bought from a tank that has fish in it. Only buy new plants from tank that have no fish in it for at least a week.
3. Early infections can go unnoticed as the Ich tends to populate the gills first and therefore can go unnoticed. This causes the fish to try to scratch the parasite by rubbing against objects.
4. Some people add salt to their tanks when performing Ich treatment. But this arguably is a waste of time. It's said that this reduces osmotic stress on the fish. But then the fish is probably already well adjusted to the osmostic pressure of your water so why stress it by altering it? You also need to ensure that you have species of fish that will not be harmed by the salt. Quite a few are. Also some species of plant don't like salty water so may die because of it weeks later. Ich isn't killed by the salt, it's the temperature which does that. At most the salty water will reduce fungus and bacteria levels which reduce secondary infections. But so will regular 25% water changes.
