HomeFreshwater aquarium fishOddballs & predatorsMarbled swamp eel Marbled swamp eel (Synbranchus marmoratus) Scientific name: Synbranchus marmoratus Bloch, 1795 The Marbled swamp eel (Synbranchus marmoratus) is a freshwater fish of the family Synbranchidae. In the aquarium it needs water at 22–34°C (72–93°F). Native range: Central and South America, Mexico to northern Argentina. Marbled swamp eel care at a glanceTemperature22–34°C (72–93°F) BiologyBody cylindrical and long; eyes small; dorsal and anal fins vestigial.Source: FishBase, licensed CC BY-NC 4.0. Species factsScientific nameSynbranchus marmoratusFamilySynbranchidae (Swamp-eels)OrderSynbranchiformes (Spiny eels)ClassActinopterygii (Ray-finned fishes)Maximum length150Common length50.0EnvironmentFreshwater; brackish; demersal; potamodromousClimateSubtropicalDistributionCentral and South America: Mexico to northern Argentina.Conservation status (IUCN)Not EvaluatedThreat to humansHarmlessUsesFisheries: commercial; aquarium: public aquariums More oddballs & predatorsParachanna obscuraLesser spiny eelMacrognathus aculeatusChanna aurantimaculataPirapatingaPiaractus brachypomusAlfaro cultratusDario darioSee all oddballs & predators SourcesTaxonomy, distribution and biology data: FishBase (Froese, R. and D. Pauly, eds.), licensed CC BY-NC 4.0.Last updated 27 September 2026