From right to left: Rhodamine B-contaminated water bottles treated with increasing quantities of heat-treated fish scales in the same duration, with a control bottle of water on the extreme left. With an increased amount of fish scales, an increased amount of the reddish dye pollutant was removed.

From left to right: Heat-treated fish scales, including some that have adsorbed the Rhodamine B pollutant, under white light, UV light and green light. Under green light, a hidden word "NUS" is formed from the fish scales that have adsorbed Rhodamine B. This underscores the scales’ potential as a material to convey concealed information.