Figure 2: A – Aspect of the gill of the control group after 7 and 20 days of experiment stained with Picrocirius Red. B - Aspect of the gill of the detergent group after 20 days of experiment stained with Picrocirius Red. C- Aspect of the gill of the Blue Lake group after 7 and 20 days of experiment stained with Picrocirius Red. Notice an increase in the reaction in the detergent group, which represents deposition of more collagen in the gill. D - Aspect of the gill of the control group after 7 and 20 days of experiment stained with Feulgen. E - Aspect of the gill of the detergent group after 7 and 20 days of experiment stained with Feulgen. F- Aspect of the gill of the Blue Lake group after 7 and 20 days of experiment stained with Feulgen. Notice an increase of nucleus size (arrows) and disorganization of the nucleus in the lamellar fusion area (asterisk).