Alligator Gar (Atractosteus spatula)

Alligator Gar (Atractosteus spatula)

The Alligator Gar is one of the largest and most powerful freshwater fish in North America, often referred to as a true “living fossil.” With its broad, alligator-like snout, armored ganoid scales, and massive size potential, this species commands immediate attention. Native to rivers and lakes across the southern United States, the Alligator Gar is a surface-dwelling apex predator best suited for very large aquariums or indoor ponds. This species is strictly recommended for advanced hobbyists due to its extreme size and long-term care requirements.

Diet

Alligator Gars are carnivorous ambush predators:

• Whole fish (tilapia, smelt, shiners)
• Shrimp, prawns, and other meaty foods
• Can be trained onto frozen/thawed foods

⚠️ Avoid feeder fish as a staple due to disease risk and poor nutrition.

Tank Requirements

• Minimum Tank Size: 300+ gallons (juveniles), indoor pond or 1,000+ gallons required for adults
• Water Type: Freshwater (can tolerate brackish conditions)
• Temperature: 68–82°F
• pH: 6.5–7.5
• Setup: Long, wide footprint with open surface area; minimal décor; tight-fitting lid required

They are surface breathers and must have access to open air.

Size

• Current Sale Size: Typically 8–16 inches

Max Size

• Maximum Adult Size: 6–10+ feet
• Can exceed 200 lbs in the right conditions

Tank Mates

Tank mates must be chosen very carefully:

• Compatible: Very large, robust species such as big catfish, gars, arowanas, and large rays
• Use caution: Most tank mates will eventually be outgrown or eaten
• Avoid: Small to medium fish, aggressive species that may harass

Realistically, best kept solo or with similarly massive fish.

Temperament

Calm and slow-moving but extremely predatory. Relies on ambush rather than active aggression. Powerful, deliberate feeder.

⚠️ Important Note

This species will outgrow nearly all standard aquariums. Long-term care requires pond-level planning and significant space.