Figure 1: A and B – Aspect of the gill of the control group after 7 and 20 days of experiment respectively stained with H-E. C and D - Aspect of the gill of the detergent group after 7 and 20 days of experiment respectively stained with H-E. E and F - Aspect of the gill of the Blue Lake group after 7 and 20 days of experiment respectively stained with H-E. Notice the lamellar fusion (arrows) and hyperplasia (asterisk).