Alligator Gar (Atractosteus spatula)

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Alligator Gar

Alligator Gar 10.JPG
Alligator Gar

Atractosteus spatula


3407 Litres (900 US G.)

300-305 cm (118.1-120.1")




7.0 - 7.5

291.483 K
18.333 °C
524.67 °R
297.039 K
23.889 °C
534.67 °R
18.3-23.9°C (65 -75 °F)

8-15 °d

1:1 M:F

10-20 years

Additional names

Alligator Gar, Gator Gar

Additional scientific names

Atractosteus adamantinus, Atractosteus lucius, Esox cepedianus, Lepisosteus berlandieri, Lepisosteus ferox, Lepisosteus spatula, Litholepis adamantinus


Native to central and south-eastern states of the USA plus northern and central Mexico. No specific type locality was provided in the original description, and it has already disappeared from much of its northern range, with modern distribution comprising the lower Mississippi River basin plus Gulf Coast states of the southeastern U.S. and Mexico, as far south as the state of Veracruz.


It is difficult to visually sex Alligator Gars.

Tank compatibility

This is the largest of the Gar species, and is therefore best kept in public aquaria for it's sheer size. It will also consume any fish it can fit in it's large mouth. Best kept alone, or with similarly-sized, non-aggressive fishes it cannot fit into its mouth.


Will eat fish, crustaceans, anything unfortunate enough to swim by! It has even been known to prey on water fowl and turtles on occassion.

Feeding regime

Gars are ambush predators feeding on smaller fishes and aquatic crustaceans in nature. It can sometimes be tricky to get newly-introduced captive individuals to accept dead foods though most will learn to do so following a short period of starvation.
After a short time most small individuals will accept meaty frozen foods such as prawns, lance fish, etc., while larger specimens can be offered whole fishes such as trout or sprats. Feed every day when juvenile but as the fish grows reduce the frequency; an adult requires only one or two meals per week at most.
In extreme cases there may be no other option but to use live “feeder” fishes for the initial period but it must be stressed that this is only advisable until an individual has built up adequate body mass to attempt a starvation period.
It’s highly recommended to buy such feeders in advance and quarantine them for at least two weeks to ensure they’re free of disease while feeding them a high quality diet so that the flesh is sufficiently nutritious.
This species should never be fed the meat of mammals such as beef heart or chicken since some of the lipids and other organic compounds contained in these meats cannot be properly metabolised by fishes, causing excess fat deposition and even organ degeneration over the long term.
Except for in the extreme circumstance described there’s also no real benefit in the use of feeder fishes due to the risk of disease or parasite introduction.

Environment Specifics

Found in various habitats from large lakes and rivers to sluggish tributaries, backwaters and pools, and can survive in both fresh and brackish waters, but shows a preference for large rivers with extensive associated floodplains. Does not tend to inhabit swiftly-flowing environments. In the aquarium, it is not too demanding provided that the water flow is not too strong and the lighting is not bright.


A solitary aggressive fish It will lurk in the reeds and plant life waiting for their food to come into reach.


These are exceptionally large fish. A mature Alligator Gar possesses a dual row of large teeth in the upper jaw. It is these remarkably alligator-like teeth which gives it its name. They have a very long body with a pointed snout, their fins are rounded and paddle-like.



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