White Spot


30 Jul 2007
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Port Elizabeth
White Spot

White spot also known as Marine Ick or by its scientific name Cryptocaryon irritans is one of the more common disease in the marine aquarium environment, luckily it is also relativity easy to diagnose and treat if caught early enough.


White spot is caused by a commonly occuring parasite, that infects fish with compromised immune systems, often caused by stress. The first symptoms of the disease usually apparent to the aquariest, are small white spots (cysts, about the size of a grain of sand) appearing on the fins of the fish. If left untreated these cysts may multiply and often even forming patches all over the fish. The infected fish may try to “scratch” these cysts by rubbing itself against either the substrate or other objects in the tank. Other symptoms that appear are; Shuddering or twitching, hyperactivity, Increased breathing rate, increased mucus production, faded colors, staying near the surface or in areas of high water flow, lack of appetite, hiding, dehydration and rapid weight loss.


The infection with white spot is usually associated with two things; the introduction of a new fish and or a compromised immune system usually caused by stress. Before introducing a new fish it is recommended to first place the fish in a bare bottomed quarantine tank, that is completely independent from your display tank. The bare bottom will allow you to easily spot, the cycts that have fallen from the fish. The quarintine tank also allows for easier treatment.
To reduce the stress in you fish, it is essential that you tank's parameters are stable, stable parameters that are slightly less than perfect are more important than parameters that may be perfect at some point in time, but fluctuate greatly.
Anecdotal evidence, suggests that adding garlic (not beetroot, lemon or African potatoes) to your fish's diet may help improve its immune system. Also ensuring that your fish if fed a well balaced diet will help its immune system.


Treatment can be divided into two categories; reef safe and not. Irrespective of which treatment you are using, it is advisable to use a quarantine tank, although this will not help if you whole tank is infected, in which case the whole tank can be treated.

Copper Treatment (not reef safe)
The most commonly used treatment method uses copper, which is not reef safe, to emphasize DO NOT USE COPPER TREATMENTS IN A REEF TANK. It is also important to remember that large doses of copper can be toxic to fish.
To treat the fish, place the fish in a quarantine tank, with a citrated copper concentration of 15ppm. Keep the fish in the system for 2 weeks, while maintaining the copper concentration. Remember to re-acclimatize you fish before adding it back to the display tank.

Malachite Green (reef safe)
The treatment using malachite green consists of three doses of malachite, one dose every second day. The dose size will depend on the size of the tank being dosed, but the ideal concentration of malachite green is per dose is 0.05 ppm.

Freshwater Dip
A five minute freshwater dip, may also help eradicate the white spot from the fish.

Commercial Medications
There are numerous medications that claim to treat white spot on the market. If such a medication is used it is best to follow the manufactures instruction.
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