Opsanus beta limit chemosensory information given to predators through a unique ‘waste’ nitrogen excretory pattern, in which urea is used to mask the scent of toadfish to predators. This ‘ureotelic strategy’ in turn makes Opsanus beta extremely resistant to ammonia challenge and thus an important model for the suite of human diseases known as hepatic encephalopathy. Hepatic encephalopathy is caused by hepatic failure resulting from chronic alcoholism, acute acetominophen toxicity, and inborn errors of the urea cycle, among other causes.