Trichodinids are the most common ectoparasites of both freshwater and marine fishes. Their generic identification is relatively easy, while the specific diagnosis is laborious due to the high intraspecific variability of some species. Four species of the genus Trichodina from the skin and fins of Oreochromis niloticus (Linnaeus, 1758) Egyptian black variety were identified by means of morphological methods and the use of digital correlation invariant to position, rotation and scale by species specific composite filters. Trichodina magna Van As Bassson, 1989 and Trichodina nigra Lom, 1961 represent new records of host and geographic location, while Trichodina centrostrigata Van As, Basson & Van As, 1998 and Trichodina heterodentata Duncan, 1977, have already been reported for O. niloticus in Mexico. The automatic identification of the four species studied was done through the developm...

Ectoparasites of the genus Neobenedenia Yamaguti, 1963, are responsible for causing mortality within aquaculture systems. Given their pronounced morphological resemblance, the identification of Neobenedenia species based on phenotypic characteristics poses significant challenges. Thus, molecular techniques are used to complement discrimination between species with very limited morphological variation, such as Neobenedenia melleni (MacCallum, 1927) Yamaguti 1963 and N. girellae (Hargis, 1955) Yamaguti, 1963. Molecular markers can enhance the ability to describe biological diversity and understand the biogeography of these species.  The gulf of California has traditionally hindered the exchange of genes for various species with different life histories. In this study, Neobenedenia specimens were collected from wild and captive Seriola rivoliana Valenciennes, 1833, at four locations wi...