Fig. 1. General view of the scaleless carp gill filaments using scanning electron microscopy (SEM) in fish exposed to normoxia (control; A), following exposure to 0.3 mg O₂ l^–1 hypoxia for 12 h (B), 24 h (C), and following 12 h recovery in normoxia (D). Note that in A, gill filaments bear short lamellae, in B there is an increase in height and basal length of lamellae, which are accentuated in C, and in D there is a reduction in height and basal length of lamellae relative to C. L, lamella; TE, trailing (afferent) edge of filament. Scale bars, 300 µm.