The term ‘fish ich’ means a fish louse with many offspring.
This is due to the fact that each parasite breeds more than a thousand offspring. The disease is alike to an infection of the skin, but it can be aggravated by poor living conditions and improper diet of the fish. Ich refers to a ciliated protozoan parasite that causes infestation in freshwater tropical fish, koi, goldfish and other species of game fish.
Fish ich symptoms include the appearance of small white spots which resemble sand. The fish also tend to scratch against surrounding gravel and rocks.
In the later stages, the dish is likely to become lethargic and redness may also develop. In some cases, blood streaks can also appear on the body of the fish. The extent to which the fish white spots cover the body may differ among infected fishes with ich. When there is severe infection, it becomes easy to detect.
However, smaller infections may go unnoticed. Infection occurs when the adult parasite makes a hole into the skin of the fish. It then feeds on the blood and dead skin cells. It is the burrowing of the parasite which results in irritation and leads to swelling of the skin. White cysts which appear as spots also develop in the process. This irritation causes the fish to rub and scratch against the rocks and gravel. After many days of feeding, the parasite turns into a trophozoite and comes out of the fish and sinks to the bottom. It produces a soft substance with a consistency of jelly, which becomes a protective membrane. It then divides into several baby parasites, called tomites. The tomites leave and go in search of fish to feed on.
Saltwater fish ich parasites are commonly present in nature and even healthy fish may be carrying some of these parasites. There is no treatment that can destroy the ich while they are burrowed in the fish. The parasites must be allowed to fall off. Medication may be used to prevent recurrence of the infestation. The infected fish must also be placed in a medicated quarantine tank where it can be treated in isolation for at least a couple of weeks. Only after that they can be added back to the main aquarium. Fish ich treatment involves raising the water temperature as this will shorten the time taken by the parasite to reach a stage where it is vulnerable to medication.