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Greater Siren

Siren lacertina

The greater siren is a massive, eel-like aquatic amphibian reaching nearly a meter long. Known to aestivate during droughts, it demands a 300L tank, heavily planted with a soft mud or sand substrate.

Taxonomy
Class:Amphibia
Order:Caudata
Family:Sirenidae
Genus:Siren
Species:Siren lacertina

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Water Temperature

18 - 26 °C

pH Value

6.5 - 7.5

Environment

Freshwater

Humidity

100 %

Day temperature

22 °C

Night temperature

18 °C

Ambient temperature

22 °C

Minimum enclosure

>= 45 L

UVB

None

Species description

Geographical Origin and Habitat: Endemic to the slow-flowing blackwater rivers, swamps, sluggish drainage canals, and turbid lakes of the southeastern United States, ranging from Virginia to Florida. As one of North America's largest amphibians, it inhabits deep, muddy waters, seeking shelter among submerged cypress roots.
Taxonomy and Genetics: A massive, eel-like neotenic salamander reaching lengths of 60 to 100 cm. It is characterized by a smooth, scaleless body covered in a thick layer of protective mucus, three pairs of reddish external gills behind a broad head, and a complete absence of hind limbs. Its small forelimbs are located just behind the gill branches.
Behavior and Habits: Primarily nocturnal and secretive, spending the day buried in thick mud or under debris. At night, it becomes an active predator, using suction feeding to capture prey. During severe droughts, it can secrete a cocoon of mucus and aestivate in the mud for several years.
Morphology: Minimal external sexual dimorphism is present. Mature females are generally larger and more robust when carrying eggs, while males may exhibit slight differences in head width during the breeding season.

Care, breeding and tankmates

Terrarium Setup: Requires a very large aquarium (minimum 120-150 cm in length, 300+ liters). The tank must be filled with deep water (30-40 cm) and the substrate must consist of fine sand or smooth mud. Gravel is strictly prohibited as it will be swallowed, leading to fatal impaction. A heavy, secure lid is mandatory as they are powerful escape artists.
Lighting and Heating: Prefers cool to moderate water temperatures between 18°C and 24°C. Water temperatures above 28°C can be fatal. Provide low-intensity aquarium lighting and ensure a stable environment, ideally in a cool room or basement.
Humidity and Hydration: Fully aquatic. High water quality is essential; use declorinated tap water or a mix with reverse osmosis water. Massive weekly water changes of 40-50% and a heavy-duty canister filter are necessary to manage their waste output.
Feeding and Supplementation: A voracious carnivore. Feed on whole defrosted fish, large earthworms, freshwater shrimp, and insects. They feed primarily by suction. Take care to avoid overfeeding, as they are prone to obesity.
Compatibility: Solitary and highly territorial. They will attempt to swallow any tankmate that fits in their mouth. House individually, as even two adults can fight and injure each other's gills.
Health and Common Diseases: Highly sensitive to ammonia spikes and elevated temperatures. Poor water hygiene can lead to bloating, skin necrosis, or the loss of their external gill branches. Avoid handling with bare hands to protect their sensitive skin.

Geographic Origin and Distribution

Endemic to the slow-flowing blackwater rivers, swamps, sluggish drainage canals, and turbid lakes of the southeastern United States, ranging from Virginia to Florida. As one of North America's largest amphibians, it inhabits deep, muddy waters, seeking shelter among submerged cypress roots.

Origin

Tropical oceans and reefsNorth America

Amphibian profile

Diet
No verified data available
Life expectancy
No verified data available
Adult size
97.8 cm
The catalog's scalar value is 97.8 cm. The AmphiBIO v1 source reports a maximum adult measurement of 97.8 cm for this species, recorded as total length (TL). These figures are not interchangeable: the first is the profile's editorial reference, whereas the second is a published maximum under a specific measurement convention; differences among sources can reflect sex, population, life stage and measuring method.
Lifestyle/Microhabitat
No verified data available
Activity cycle
No verified data available
Sociality
No verified data available
Reproduction
No verified data available
Toxicity
No verified data available
Life stage
No verified data available
Handling tolerance
No verified data available
Brumation
No verified data available
Molting
No verified data available

Image gallery

Licensed images linked to the species or, when marked, to the closest representative taxon.

Related species

Recommendations grouped by close relatives, companion choices, and similar care.

Variants and close relatives

Same atlas type, nearby scientific identity, genus, or family.

Last updated: 08/10/2026
Greater Siren (Siren lacertina) Care Guide & Terrarium Setup | Atlarium