Description

Symptoms: salt-like specks on the body/fins, excessive slime, problems breathing (Ich invades the gills), clamped fins, loss of appetite.

This disease, which is the most common malady experienced in the home aquarium, is caused by a parasite (from the group of ciliates) and is easily cured if caught in time. However, since the parasite on the fish is "protected" by the fish's mucous membrane, a medication cannot kill the parasite while it is on the fish.

Normally, to the amateur aquarist, the life cycle of a parasite is of no importance. However, since this parasite is susceptible to treatment at only one stage of the life cycle, an awareness of the life cycle is important.

• Adult phase - it is embedded in the skin or gills of the fish, causing irritation (with the fish showing signs of irritation) and the appearance of small white nodules. As the parasite grows it feeds on red blood cells and skin cells. After a few days it bores itself out of the fish and falls to the bottom of the aquarium.
• Cyst phase - after falling to the bottom, the adult parasite forms into a cyst with rapid cell divisions occurring.
• Free swimming phase - after the cyst phase, about 1000 free swimming young swim upwards looking for a host. If a host is not found within 2 to 3 days, the parasite dies. Once a host is found the whole cycle begins anew.

Treatment

Only during the free swimming phase is a successful treatment possible.

The three phases mentioned above take about 4 weeks at 21°C but only 5 days at 27°C. For this reason it is recommended that the aquarium water be raised to about 27°C for the duration of the treatment. If the fish can stand it, raise the temperature even higher up to 29°C (but not over 30°C). Raising the aquarium temperature to 27°C will greatly shorten the time for the free swimming phase to occur.

Prior to the use of any medication, it is recommended to siphon out the gravel thoroughly in order to remove as many as possible of the cysts of the pathogen that are present on the bottom. Please remove any activated carbon from the filter for the duration of the medication use. UV-C appliances and CO₂ fertilizing appliances also need to be switched off. Change 50 % of the water prior to application of any medication. Aerate the aquarium using a diaphragm pump with airstone during the treatment. Filter during the treatment. The filter must be cleaned prior to use of medication.

Some aquarists like to use malachite green, but it tends to stain the plastic and silicone in the aquarium. Most commercial remedies contain malachite green and/or copper, which are both effective.

After treatment

After the treatment, please filter the aquarium water for 24 hours using activated carbon to remove the residues of medication. Afterwards the activated carbon should be duly discarded. The addition of a bacterial starter to the aquarium water helps to replace any purifying bacteria which may have been affected. Please check during the treatment and daily in the first days after the treatment the ammonium/ ammonia and nitrite values. With nitrite values of over 0.5 mg/l an immediate water change of 50% should be carried out and a bacterial starter added.