We report the details of a case of toxicosis in two four-month-old mixed breed dogs by the Caribbean Sharp-nosed Pufferfish, Canthigaster rostrata, a small but lethally neurotoxic marine fish that contains tetrodotoxin (TTX) as well as potential saxitoxins (SSXs). Following consumption of at least 30 juvenile C. rostrata individuals, one dog showed gastrointestinal and neurological symptoms indicative of presumptive TTX poisoning that endured for four to six hours. The dog recovered within six to 12 hours following treatment with activated charcoal. The second dog consumed five to ten juvenile C. rostrata individuals and exhibited no major side-effects. To our knowledge, this is the first report of dogs poisoned by C. rostrata, which contributes to the present understanding of tetrodotoxin toxicosis and treatment in canines. We document this case to bring awareness of this potential risk to pet-owners and veterinarians working in coastal Neotropical areas.