Background

Trichodina is very common in small populations, which do not pose a threat to the goldfish health. While most parasites will feed on the host, Trichodina does not feed on goldfish but goes use the host goldifsh as a home, and for transportation. In larger number however, trichodina can be very irritating to the goldfish's skin, often resulting in some tissue damage. Severe infestations of trichodina are often associated with;

• Overcrowding
• Poor water quality 

Diagnose

This parasite is easy to recognize, noticably skimming over the surface of the skin and gills. Goldfish symptoms will often include:

• Irritated skin
• Flashing and Scratching
• Ulcers 
• Lethargic
• Isolated
• Stop Feeding
• Lay on the bottom of the fish tank
• Clamped fins.

Treatment

Trichodina can be tricky to treat in some cases, but the best treatment against Trichodina is potassium permanganate. This is most effect, and works almost every time. If dealing with a small number (1-2) of goldfish, a salt bath is recommended.