The ethanol collections of the Africamuseum require an approved denaturing agent, that can be used to top-up containers in which, historically, camphor-denatured ethanol has been used. Denatonium benzoate, diethyl ether and isopropyl alcohol were evaluated on their ability to preserve Lithobates catesbeianus (Shaw 1802) in the long term. There was no visual difference between the colors of the preservation liquids over time, but precipitates were formed in almost all of the test containers. The snout-urostyle length and the length of the thigh of the test specimens were assessed over time. After artificial aging, specimens in a mixture of ethanol denatured with isopropylalcohol shrunk less than those in other mixtures, even the control group, albeit by only a small fraction.