TnP is a peptide, or short protein fragment, from the venomous toadfish Thalassophreyne nattereri, found along Brazil’s northern and northeastern coasts. It has shown anti-inflammatory and anti-allergic effects, as well as preliminary effectiveness in treating MS and asthma in mouse models of those conditions. Researchers at the Butantan Institute Special Laboratory for Applied Toxicology, in São Paulo, Brazil, recently found that TnP can delay the onset of more severe MS symptoms in mice and lessen their impact. But the toxicity of this compound has yet to be addressed in animal studies. The zebrafish, a common laboratory animal used in early drug development, is deemed a good candidate to test toxicity as an alternative to rodents and other mammals. It shares about 70% of its genome with humans and has conserved metabolism and physiology.