A primitive, highly predatory fish native to North America. Known for its extremely elongated snout filled with teeth and tough, armor-like ganoid scales. As an ambush predator that breathes atmospheric air, it often hovers motionless near the surface. Due to its massive adult size, it is strictly considered a 'Monster Fish' suitable only for massive custom enclosures, indoor ponds, or public aquariums. It will consume any tank mate small enough to fit in its mouth.
Longnose Gar At a Glance
Longnose Gar Tank Requirements
Will Longnose Gar fit in your tank?
Care guides tell you what Longnose Gar needs, the next question is whether your tank can safely provide it. Test Longnose Gar against your tank size, maintenance needs, and the fish you already keep before you buy.
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Longnose Gar Water Parameters
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Longnose Gar Temperament & Compatibility
Longnose Gar Varieties
Each variety inherits the species defaults above. Only differences are highlighted.
Standard Adult
Fully grown adult. Requires a massive custom tank or heated pond. Must be kept with similarly sized, robust fish to avoid predation.
Differs in 1 trait from base species
Also known as: Adult Gar, Monster Fish
Juvenile (Grow-out)
Young specimens commonly sold in the trade. While they can be kept in standard large aquariums temporarily, they grow extremely fast and will rapidly outgrow standard tanks. They are highly prone to damaging their delicate snouts if panicked.
Differs in 4 traits from base species
Also known as: Baby Gar, Juvenile
Longnose Gar Care Guide Summary
The Longnose Gar, scientifically known as Lepisosteus osseus, belongs to the Oddballs family group. Adults reach a maximum size of approximately 150 cm and have a fusiform body shape with a fast growth rate. Classified as aggressive, this species primarily occupies the surface and mid-level zones of the aquarium and produces a extreme level of biological waste.
To thrive, the Longnose Gar requires a brackish tolerant aquarium with a minimum volume of 4000 litres and a tank length of at least 360 cm. Water temperature should be maintained between 12°C and 28°C, with a pH range of 6.5–8.5 and a general hardness of 8–25 dGH. A low water flow is preferred.
Due to its specialist needs, the Longnose Gar is best suited for fishkeepers who can provide a carefully planned setup. This species is available in 2 varieties: Standard Adult and Juvenile (Grow-out). Each may differ slightly in size, temperament, or care needs, so it is worth checking the specific requirements of the variety you plan to keep.
Longnose Gar Habitat Setup
When setting up an aquarium for the Longnose Gar, a low water flow best suits their natural preferences. Because this species occupies the surface and mid-level zones, the aquarium layout should prioritise adequate surface area with floating cover to make them feel secure near the waterline and open swimming space in the centre of the tank for free movement. Useful additions include smooth gravel or rounded substrate to protect their sensitive barbels and floating plants to diffuse overhead light and create shaded areas. Keepers should note that a tight-fitting lid is essential, as this species is a known jumper.
Longnose Gar Compatibility Notes
Classified as aggressive, the Longnose Gar is adaptable and can be kept singly or in a small group, offering flexibility when planning a community tank. When choosing tankmates, any fish small enough to fit in its mouth will likely be eaten and ornamental shrimp are not safe companions. Selecting tankmates that favour different water layers from the surface and mid-level zones can help reduce competition and territorial overlap.
Longnose Gar Feeding & Diet Considerations
The Longnose Gar is a predatory species that will readily consume small fish, so nano or bite-sized tankmates should be avoided, will hunt and eat ornamental shrimp, making it unsuitable for shrimp-focused setups, and will eat fry, so breeding efforts in the same tank are unlikely to succeed.
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Frequently Asked Questions About Longnose Gar
How big does Longnose Gar get?
Longnose Gar (Lepisosteus osseus) typically reaches a maximum adult size of approximately 150 cm. They have a fusiform body shape and a fast growth rate.
What tank size does Longnose Gar need?
A minimum aquarium volume of 4000 litres and a tank length of at least 360 cm are recommended for Longnose Gar. This ensures enough swimming space and helps maintain stable water conditions.
What water parameters does Longnose Gar need?
Longnose Gar thrives in brackish tolerant conditions with a temperature range of 12–28°C, a pH between 6.5 and 8.5, and a general hardness of 8–25 dGH. A low water flow is preferred.
Is Longnose Gar peaceful or aggressive?
Longnose Gar is classified as aggressive with an aggression score of 7 out of 10. Careful tankmate selection is essential to avoid conflict.
Can Longnose Gar live alone?
Yes, Longnose Gar can be kept singly or in a group. They are flexible and adapt well to both setups.
Is Longnose Gar safe with shrimp?
No. Longnose Gar is known to eat ornamental shrimp and is not recommended for shrimp tanks. Even larger shrimp species like Amano Shrimp may be at risk.
Does Longnose Gar have any special tank requirements?
Yes. Longnose Gar benefits from plants - floating and smooth gravel (sensitive barbels) in the aquarium. These features help replicate their natural habitat and promote overall health and well-being.
Does Longnose Gar need a lid on the tank?
Yes. Longnose Gar is a known jumper, and a tight-fitting lid or cover is essential to prevent escape. Even a small gap can be enough for a determined fish to leap out.
Plants That Suit Longnose Gar
These plants pair well with Longnose Gar based on shared water preferences, layout fit, and how likely they are to hold up in the same aquarium.
Amazon Frogbit
Limnobium laevigatum
Asian Watergrass
Hygroryza aristata
Asian Watermoss
Salvinia cucullata
Carolina Mosquito Fern
Azolla caroliniana
Common Duckweed
Lemna minor
Crystalwort
Riccia fluitans
Fish Similar to Longnose Gar
Alligator Gar
Atractosteus spatula
A massive, primitive ambush predator native to North and Central America, known for its crocodilian snout and armor-like ganoid scales. They grow to enormous sizes and are strictly for public aquaria or highly advanced monster fish keepers with massive custom indoor ponds. They are air-breathers and incredibly hardy, but their size makes them entirely unsuitable for standard home aquariums.
Florida Gar
Lepisosteus platyrhincus
A prehistoric, heavily armored ambush predator native to the southeastern United States. They possess an elongated, torpedo-like body and a beak filled with sharp teeth. As an apex predator, they will consume any tank mate that fits in their mouths, but are generally peaceful toward fish too large to eat. They require massive aquariums and a secure, weighted lid due to their powerful jumping capability.
Needlenose Gar
Xenentodon cancila
A fascinating, highly predatory surface-dwelling fish with a long, beak-like mouth filled with sharp teeth. Despite the common name, it is a needlefish, not a true gar. They are notoriously skittish and prone to fatal jumping or injuring their delicate snouts on tank walls if startled. They strictly require a tight-fitting lid and a very long tank with open swimming space at the surface.
Cuban Gar
Atractosteus tristoechus
The Cuban Gar (Manjuarí) is a massive, ancient ambush predator native to the fresh and brackish waters of Cuba. It features a crocodilian snout, heavy armor-like scales, and a torpedo-shaped body. Due to its extreme adult size, it is strictly recommended only for expert aquarists with indoor ponds or enormous custom tanks. It will swallow any tank mate small enough to fit in its jaws, but generally ignores fish that are too large to eat.
Arrowhead Puffer
Pao suvattii
A highly predatory freshwater pufferfish native to the Mekong basin. Named for its V-shaped, flattened head, it is a specialized ambush predator that buries itself in sand with only its eyes and upwards-facing mouth exposed. It is notoriously aggressive and will consume or fatally bite any tankmate, regardless of size. Must be kept strictly solitary.
Indonesian Datnoid (Tiger Fish)
Datnioides microlepis
A massive, deep-bodied ambush predator highly prized by monster fish keepers for its striking black and gold 'tiger' stripes. Native to the freshwater rivers of Southeast Asia, they possess huge mouths and will consume any fish small enough to fit. They are notoriously shy when young but grow into bold, impressive centerpieces. Due to intense conspecific aggression, they should be kept entirely solitary or in groups of 4 or more to disperse bullying.