Vermiculated Sailfin Catfish, Pterygoplichthys disjunctivus
Vermiculated Sailfin Catfish, Pterygoplichthys disjunctivus. Fish caught from an irrigation canal along the Tamiami Trial, Tamianmi, Florida, December 2018. Length: 20 cm (7.9 inches). Catch, photograph, and identification courtesy of Kenneth Tse, Toronto, Ontario, Canada.
Vermiculated Sailfin Catfish, Pterygoplichthys disjunctivus. Fish caught from an irrigation canal within residential Orlando, Florida, July 2017. Length: 61 cm (20 inches). Catch, photograph and identification courtesy of Luke Ovgard, Klamath Falls, Oregon.
The Vermiculated Sailfin Catfish, Pterygoplichthys disjunctivus, is a member of the Suckermouth Armored Catfishes or Loricariidae Family, that is known in Mexico as plecóstoma rayado or simply bagre. The Loricariidae Family is the largest catfish family with 680 recognized species. Globally, there are sixteen species in the genus Pterygoplichthys, four of which are found in the freshwater systems of mainland Mexico.
The Vermiculated Sailfin Catfish has an elongated and easily recognizable “catfish-like” body with an inferior suction mouth and two maxillary barbels on the ventral side. Their body is covered with dark and light vermiculations of equal width. Their dorsal fin has light spots and become chevrons posteriorly. Their adipose fin has 1 spine, their anal fin has 4 rays; their dorsal fin has 1 spine and 12 rays; their pectoral fins have 2 spines and 6 or 7 rays and their pelvic fins have 5 or 6 rays. They are well protected by bony modified scales, their adipose fin has a spine and their pectoral fins have thick serrated spines that provide a strong defensive. They reach a maximum of 70 cm (2 feet 4 inches) in length and 2.0 kg (4 lbs 6 oz) in weight. They have an acute sense of smell. They are benthic feeders that forage along the bottoms of streams and lakes consuming benthic algae and detritus. At present they have no known predators. The males are different in appearance compared to the females, having a small thick stump protruding from the fish’s undercarriage. Reproduction occurs in large aggregations as an asynchronous, multiple spawning event, where the males dig out large burrows in river banks, attracting females who lay eggs which the males then fertilize and guard until they hatch.
The Vermiculated Sailfin Catfish is found in a wide variety of habitats, ranging from relatively cool, fast-flowing and oxygen-rich highland streams at elevations up to 3,000 m (10,000 feet) to slow-flowing, warm lowland rivers and stagnant low-quality pools with low oxygen content. They can also survive in brackish water environments and can breathe air and survive out of water for up to 20 hours, an ability attributed to their specialized enlarged stomach. Their population expansions are only limited by their lower lethal temperature which is around 10oC (50oF). The Vermiculated Sailfin Catfish is poorly studied with very limited information available about their lifestyle and behavioral patterns including specific details on age, growth, longevity, movement patterns, diet, habitat use, and reproduction.
The Vermiculated Sailfin Catfish can be distinguished from the North American Catfishes of the Ictaluridae Family via its ventral mouth. They are often confused with Hypostomus (7 or 8 dorsal fins). They are most likely confused with the Amazon Sailfish Catfish, Pterygoplichthys pardalis (abdomen with spots, 8 dorsal rays).
The Vermiculated Sailfin Catfish is native to the Amazon River basin of South America. They have been widely introduced in several countries outside their native range, predominantly by aquarium releases, and first showed up in Mexico in 1995. They have been documented in freshwater systems of the states of Chiapas, Guerrero, Michoacán and Tabasco. It is more than likely that due to their high level of invasiveness they will be currently present in several other locations.
From a conservation perspective the Vermiculated Sailfin Catfish has not been formally evaluated. Their long-term survival is threatened by competition from other catfishes and large amounts of fungicides, herbicides and pesticides from agricultural run-off. Due to their highly invasive nature they have become or will soon become pests in several locations. They generate a large amount of silt, destabilize river banks by their nest building which increases erosion, and disrupt aquatic food chains. They are utilized by the aquarium trade at a small level, compete for food with native species, disrupt endangered shore birds, and change aquatic plants feeding behaviors. At present they are not consumed by humans.