Figure 3. Hymeniacidon perlevis in the drainage conduit of the land-based fish farm during the observation period.

(A) PVC frames G, H and I at the beginning of the observation positioned on the sponge showing a brownish color; (B) the same frames at the end of the observation period covered by sponge displaying an external cream color; (C) in the PVC frame F, H. perlevis shows a necrosis area (red arrow) next to the dry fish food residues (pellet, white arrow).