Fish Anchor Worm

  • Main symptoms: Small visible parasites 0.5 to 1.5 mm long, which invade the skin and gills. The parasite anchors itself by the head in the fish’s skin, feeds on it and deposits its eggs there: after hatching, the small parasites leave in search of a host.
  • Secondary symptoms: The fish rubs against the stones or tank decoration. Fish is listless. Loss of appetite. Respiratory problems (rapid or labored breathing) and even suffocation if the gills are infected. Sometimes, clamped fins and red and inflamed skin irritation.
  • Direct causes: Parasitic crustaceans (they are not worms).
  • Contagious : Yes.
  • Severity: Act quickly to avoid multiplication of the parasites (it is very contagious). The anchoring zone of the parasite is weakened and favors the appearance of infections (fungi, bacteria…) which are sometimes fatal. A large number of parasites can also impede breathing when the parasites colonize the gills.
  • Treatments: Only a few treatments are commercially available – Interpet Anti Crustacean Parasite, JBL Aradol Plus or Waterlife Parazin). If there are only one or two parasites, they can be removed manually if the fish is not too small: by holding it firmly but without squeezing it in a wet cloth (so as not to damage the scales), remove the parasite with tweezers before disinfecting the wound with a little betadine. Note that sometimes, unfortunately, the anchor part of the parasite can remain embedded under the skin. Isolate the affected fish to avoid contamination of other fish by larvae (as egg bags often tear, releasing juveniles) in a quarantine tank. Details about the procedure can be found on the following website:
  • Occurence : Uncommon in fish tanks. More common with cold water fish and especially in ponds.
Anchor Worm

Anchor Worm: close view

Anchor Worm

Goldfish infested by anchor worms

Exclamation markImportant: do not forget to remove the activated charcoal during the entire treatment (as it will absorb the medication). It can be put back in the aquarium at the end of the treatment to remove the residues.
Exclamation markImportant: Whilst all care is taken to provide accurate information on this website, Web Goldfish accepts no responsibility in the case of mis diagnosis of diseases/ incorrect treatments or any other errors made. In case of doubt, please always consult a veterinarian.