Lepeophtheirus pectoralis copepodid stage, during which the copepod attaches itself to the fish. Stages IV, V, VI and VII are the chalimus stages, and are followed by the pre-adult and adult stages, when differentiation of males and females is possible. Lepeophtheirus pectoralis Lepeophtheirus pectoralis is a species of parasitic copepod. It is a parasite of flatfish, the most frequent hosts being the European flounder ("Platichthys flesus"), the plaice ("Pleuronectes platessa"), and the dab ("Limanda limanda"). It feeds on the mucus, skin and blood of the fish, with oviferous females being found in the pectoral and pelvic fins of the host, while immature
Eclecta aurorella by a slender white line. There is an irregularly triangular dark reddish-fuscous blotch, more ochreous-fuscous beneath, on the hindmargin, its apex extending to the disc at three-fifths from the base, its base extending from above the anal angle to beneath the apex, the lower side suffused, upper side connected in the disc with a dark reddish-fuscous acute diamond-shaped mark beneath the costa, beyond the connection margined with white. Within this triangle is a slender white twice sharply-toothed line proceeding from the middle of the upper side to the lower angle, and two small indistinct whitish spots on the hindmargin. The