Name of disease: Ich
Other names: White Spot
Type of disease: Parasite
Occurrence: Very common, affects all types of freshwater fish
Symptoms include: White spots like grains of salt on the fish's fins and body, thickened slime coat, clamped fins, fish flicks/rubs itself against objects in the tank, faster gill movements, fish stops eating. Can be distinguished from Velvet Disease by the larger, more rounded and whiter spots.
1. Ich organisms are introduced into the tank via new fish / plants / ornaments and infect other inhabitants. (This can be prevented by quarantining new arrivals and disinfecting plants etc. with a potassium permanganate solution).
2. Ich organisms are already present at a low level (causing no problems to the fish), but a sudden cause of stress such as poor water quality lowers the fish's immune resistance and causes infection.
Treatment: Ich has a free-swimming stage in its life-cycle so the whole tank must be treated, not just the affected fish. Do not use a hospital tank for this reason. EITHER treat with salt at a .3% solution OR with medications containing Malachite Green, Formalin or Copper (examples: Rid-Ich (US), Protozin (UK)). Increase tank temperature to high 70's and if using a Malachite Green medication keep tank completely dark and covered over. Continue treatment until fish have been completely ich-free for at least 3 days, ideally 6 days. Vacuum the substrate thoroughly after treatment has finished to remove any remaining parasites in tank.
Precautions: Check water quality regularly during treatment as both salt and meds can affect the cycle. Due to its life-cycle, ich can re-occur after treatment has finished; if this happens re-start treatment and do not stop until fish have been ich free for at least 6 days.
The photo below shows a Common Goldfish with Ich.