Name of disease: Fish lice
Other names: Argulus
Occurance: Very common parasite, can be found in pet stores all over the world.
Appearance and symptoms: Fish lice are one of the very few parasites that are visible with the naked eye. Easily recognized in its green disk like shape, often with 2 visible eyes, and can move around on the fish. Symptoms, besides the obviously visible disk, are scratching and rubbing against objects, and tiny red spots where the hooks held on to the body and gills.
Treatment: Best treated with medication containing Diflubenzuron, like Anchors Away (treat as directed on the package) or Dimillin (3 times with 6 days apart). The visible fish lice should be taken off of the fishes body with tweezers, the red spot that the hooks leave behind, needs to be treated with neosporin or Panalog.
Background: The fish louse is a very dangerous parasite. Its hooks can go into the fishes skin and gills and causes extreme irritation. Due to the open wound the fish is suspectible to secondary infections like bacterial gill disease and ulcers. Besides the physical injuries to the fish, the constant irritation causes stress, which might lead to secondary parasite attacks like Ich and Costia.
The fish lice will lay eggs all over the tank on plants and ornaments, and after a few days those mini lice will go out and try to find a host on their own. the whole process take 30-100 days, depending on the temperature. It is therfore very important, to have follow up treatments.
Anybody having a picture of an invested fish with the lice clearly visible, feel free to put it up here....