Balloonfish, Diodon holocanthus
The Balloonfish, Diodon holocanthus, whose common Spanish name is pez erizo mapache, and known locally as botete, is a species in the Porcupinefish or Diodontidae Family, known collectively as pez erizo in Mexico. Globally, there are only seven species in the genus Diodon, four of which are found in Mexican waters, two in both the Atlantic and the Pacific, one in the Atlantic and one in the Pacific.
The Balloonfish have robust, oval, and inflatable bodies, which feature a wide blunt head, a pair of small barbells on the chin, disproportionately large eyes, strong parrot-like teeth on both jaws, and a large mouth. Dorsally they are light olive to pale brown in color with their shading changing to white ventrally. Their upper head and body are covered with small black spots. The black spots on their belly become very prominent when the fish are inflated. There are brown bars running from above to below their eyes, across their upper back, and a shorter bar across the middle of their back. They have a large oval brown blotch above each pectoral fin and another around the dorsal fin base. Their fins are without spots, which is a key to identification. Their body and head are covered with numerous long, erectile, slender, and round spines; a row of 12 to 16 erectile spines run from the top of their snout to their dorsal fin. Their caudal fin base is spineless.
The Balloonfish are found inshore near the bottom in and around protected areas that offer shelter such as caves, shipwrecks, reefs, ledges and within coral and rocky reefs and open sand rubble bottoms at depths up to 330 feet. The Balloonfish reach a maximum length of 50 cm (19.7 inches) but are common at lengths of 25 cm (10 inches). Balloonfish are nocturnal predators consuming crabs, snails, and urchins and are generally found hiding in crevices during the day. Juveniles are pelagic with an open oceanic lifestyle until reaching 15 cm (6 inches) in length, after which they move to coastal environments and become benthic. They are preyed upon by large carnivorous fish including dorados, sharks, and wahoos. They are capable of expanding their body size by taking in water and inflating, which they use as an effective defense mechanism.
The Balloonfish are a circumglobal warm water species found in all tropical waters of the globe. In Mexican waters they are found in all waters of the Atlantic and the Pacific with the exception that they are absent from the extreme northwest section of the Sea of Cortez.
The Balloonfish is straightforward to identify noting that the similarly-appearing Porcupinefish, Diodon hystrix, the Pelagic Porcupinefish, Diodon eydouxii, and the Spotfin Burrfish, Chilomycterus reticulatus, but all of these have spotted fins.
The Balloonfish is fairly common and readily accessible via surf fishing at certain times of the year in the greater Los Cabos area. The Balloonfish are considered a “catch and release” as they might contain the potent neurotoxin tetrodotoxin, thus I strongly recommend that they not be used for human consumption. They are used on a very limited basis to make curios and sold in local Mexican markets as house decorative items. They are also fairly common in public aquariums and used on a limited basis in Asian medicinal practices.
Balloonfish, Diodon holocanthus. Fish caught from shore at Los Barriles, Baja California Sur, January 2018. Length: 18 (7.1 inches). Catch courtesy of Kyle Rousseau, Maple Ridge, British Columbia, Canada. Photo courtesy of Brad Murakami, Surrey, British Columbia, Canada.
Balloonfish, Diodon holocanthus. Underwater photo taken in coastal waters off Buena Vista, Baja California Sur, June 2017. Length: 23 cm (9.0 inches). Photo courtesy of Bob Hillis, Ivins, UT.
Balloonfish, Diodon holocanthus. Three different fish caught from shore at Km 21, Cabo Real, Baja California Sur, June 2008. Length: all a consistent 25 cm (10 inches). A fish with personality that provides unique photographic opportunities.
Balloonfish, Diodon holocanthus. Fish caught off Point Palmilla, Baja California Sur, November 2017. Length: 40 cm (16 inches). Catch courtesy of Mauricio Correa, Los Cabos, Baja California Sur.