Water Mites

Water mites are spider-like arthropods related to terrestrial mites and ticks. Water mites are characterised by having four pairs of legs, no antennae, and two pairs of appendages on the head called chelicera and pedipalps. Water mites inhabit a wide range of aquatic habitats and are generally not considered as fish parasites. However, under certain environmental conditions they may proliferate and subsequently colonise weak or stressed fish.

There has been one report of a water mite species, Histiostoma papillata, attacking and apparently killing juvenile Murray Cod held in a recirculating aquaculture system. Fish infested with this mite were listless and had difficulty swimming upright. The fins were damaged and showed signs of haemorrhaging at the bases. Mites were found on the fins, body surface and gills. Large numbers of mites were also found in detritus on the bottom of the tanks and in other parts of the recirculation system. Prevention of water mite infestations should include maintenance of hygienic conditions and water quality and reducing and avoiding stressful conditions.