Gulper Catfish (Asterophysus batrachus)

The Gulper Catfish is one of the most extreme freshwater predators in the aquarium hobby. Famous for its massive mouth and ability to swallow prey nearly its own size, this species is a true ambush hunter.

Native to South America, this rare catfish spends most of its time motionless—until it strikes in a split second. If you’re looking for a unique, conversation-starting predator, this is it.

Max Size

• 8–12 inches in captivity
• Compact body, oversized mouth

Tank Size

• Minimum: 40–55 gallons (single specimen)
• Recommended: 75+ gallons for stability and long-term care
• Does not require large swimming space but benefits from stable conditions

Tank Mates

• Best kept alone
• Will eat anything that fits in its mouth (which is almost everything)
• Not suitable for community tanks

Diet

Strict carnivore:

• Live feeder fish (use caution and ensure quality)
• Frozen/thawed fish, shrimp, and worms
• Can sometimes be trained onto non-live foods

👉 Known for swallowing prey whole—one of the most aggressive feeding displays in the hobby

Care & Behavior

• Nocturnal and sedentary—often hides during the day
• Prefers dim lighting and minimal disturbance
• Ambush predator—will sit still for long periods before striking
• Requires clean, well-filtered water despite low activity

Why We Love Them

• One of the most unique feeding behaviors in freshwater fish
• Rare and highly sought-after species
• Compact size with extreme predator traits
• Perfect for species-only display tanks

⚠️ Important Notes

• Can choke on oversized prey—feed appropriately sized meals
• Not beginner-friendly due to feeding challenges
• May refuse non-live food initially
• Not compatible with other fish