Gulper Catfish: A Guide to This Weird and Wonderful Fish

Alison Page

Alison Page


Gulper Catfish

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Are you looking for something a little bit different to add to your freshwater fish tank? Well, the Gulper catfish might be a critter you could consider if you have a big aquarium.

So, what is a Gulper catfish? Are Gulper catfish good beginner fish? And what tank mates are suitable to live with adult Gulper catfish?

Read this comprehensive guide to learn how to keep Gulper catfish successfully in your home aquarium.

Gulper Catfish – Overview

Gulper Catfish Info
Scientific nameAsterophysus batrachus
Common namesGulper catfish, Ogre catfish
Care levelAdvanced
BehaviorNocturnal predatory fish
Size12 to 14 inches
Lifespan8 to 15 years
Minimum tank size100 gallons. Ideally, the tank should measure 72 x 18 x 18 inches.
Water temperature750 to 840 Fahrenheit
Water parameterspH 5.6 to 6.8, water quality soft and slightly acidic

What Is a Gulper Catfish?

The Gulper catfish, scientific name Asterophysus batrachus, is a member of the Auchenipteridae family of driftwood or auchenipterid catfishes.

These fish are native to rivers ranging from southern Central America to Argentina in South America. All the auchenipterid catfish have a scaleless body, and almost all have three pairs of barbels, with the maxillary pair being the longest.

Most species of Gulper catfish are freshwater fish, although the Pseudauchenipterus nodosus variant is known to live in brackish conditions occasionally.

Gulper Catfish Natural Habitat

Gulper catfish are native to northern South America, specifically Brazil and Venezuela’s Rio Negro and Rio Orinoco drainages.

These fish inhabit slow-flowing habitats that are full of submerged structures and vegetation. Gulper cats are rather bulky and are not particularly strong swimmers. That makes it difficult for the fish to tolerate fast-moving, strong currents. That said, some hobbyists keep their Gulper cats in large tanks with a turnover rate of as much as 20 times the aquarium volume.

However, if you want to run a strong filtration system to keep the tank clean, we recommend using tank decor such as driftwood to disrupt the flow.

Gulper Catfish Appearance

Wild Gulper cats grow to between 12 and 14 inches in length, although captive specimens are somewhat smaller, reaching around 10 inches.

These weird-looking fish resemble some kind of deep-sea creature more than a freshwater catfish! The mouth is downturned, and the fish have the typical whiskers or barbels of other catfish species. Gulpers have bulbous, rotund bodies, tiny beady eyes, and huge gaping mouths.

Gulper catfish come in several colors ranging from light brown to orange to black on top and a white, distended belly.

The fish’s fins are quite small compared to the rest of the body. Gulpers have an adipose and dorsal fin, a broader caudal, two smaller pectorals, two pelvic, and one anal fin. Avoid touching the dorsal and pectoral fins when performing routine maintenance tasks in your aquarium. Those fins have very sharp rays that can inflict a painful nick.

When you buy a Gulper catfish, check to see that the seller hasn’t clipped the rays. That’s done to prevent the fish from slicing through the bag used to transport them but cutting the Gulper’s rays can cause infection.

Male vs. Female Gulper Catfish

Male Gulper catfish are generally narrower and smaller than females, which typically grow to 1 inch or so larger than males. Males have larger heads than females, and their fins are generally longer and more brightly colored.

Female fish are usually 1.5 inches wider than males to provide room for the eggs during the spawning season.

How Long Do Gulper Catfish Live?

Taking on a Gulper catfish is a long-term project, as these fish can have a lifespan of around 8 to 15 years in captivity.


Gulper catfish are not easy to come by. Although they don’t yet appear as assessed on the IUCN Red List of endangered species, Gulpers are uncommon in the wild and are not exported very often.

Sometimes, you can buy wild-caught Gulper catfish online and expect to pay around $120 or upward.

Gulper Catfish Care Guide

In this part of our guide, we successfully discuss how to care for the Gulper catfish in your home aquarium.

Tank Size

As previously mentioned, the Gulper catfish can grow to around 14 inches in length, so you need a tank of around 100 gallons to accommodate one.

That said, the tank’s “footprint” is important when keeping one of these creatures rather than the volume in isolation. Ideally, your 100-gallon tank should measure roughly 72 x 18 x 18 inches to accommodate the fish’s conformation and behaviors. Unfortunately, that aquarium footprint is not generally available as standard, although you can have one custom-made.

Tank Decoration

Gulper catfish are nocturnal, spending daylight hours hiding underneath overhangs or beneath pieces of wood. Gulper catfish have soft, scaleless skin that’s highly sensitive to injury by sharp or rough objects and surfaces. For that reason, we recommend taking a minimalist approach to your aquarium’s overall decor.

Gulper cats are a species of wood catfish found in areas with lots of submerged structures in the form of fallen branches, driftwood, and the like. So, it’s a good idea to replicate that environment in your fish tank. You can use any wooden decorations, provided the pieces are not rough and don’t have sharp points that might injure your fish.

When it comes to substrate selection, it doesn’t really matter what kind of media you choose. We recommend choosing a rounded pebble substrate or similar and avoiding large gravel with sharp edges. As a good rule of thumb, if you can run your fingers through the substrate a few times without your skin being chafed, then the substrate is probably a safe choice for Gulper cats.


Like all large carnivores, this species of catfish tends to make a mess in the tank. For that reason, you’ll need a filtration system that can cope with the volume of waste the Gulper catfish produces.

However, like many other catfish species, Gulpers aren’t fussy when it comes to water quality and will tolerate less than pristine water conditions. That’s not an excuse for not maintaining your aquarium properly! And remember that your other livestock might need stable, clean conditions.

As mentioned previously, Gulper catfish come from slow-moving water bodies. These fish don’t appreciate a strong current in their habitat, so you’ll need to buffer the filter unit outflow to prevent the fish from becoming stressed.

Water Parameters

Gulper catfish are tropical fish that need a water temperature of between 75 and 84 degrees Fahrenheit.

The pH should be in the range of 5.6 to 6.8, and water that is generally soft and acidic.

Tank Maintenance

Although Gulper catfish are not especially fussy when it comes to tank cleanliness, they cannot tolerate extremes and massive swings in water quality.

So, you need to carry out frequent water changes, ideally every week, to keep the conditions clean. Use an aquarium vacuum cleaner to remove any organic waste from around the substrate and underneath decorations.

Test the replacement water to ensure that it’s the same temperature, pH, and hardness as the aquarium water. That prevents causing stress to your livestock.

What Do Gulper Catfish Eat?

Gulper catfish are carnivores adapted to consuming large prey items relative to the fish’s size.

The fish’s huge mouth extends to the back of the creature’s head, and the Gulper’s skin can stretch to cope with especially big meals. Gulpers can easily gobble up fish half their size. You should also note that these fish have been killed and severely injured by attempting to eat a fish that’s just too big to handle!

Like most captive catfish species, Gulpers will generally readily accept prepared foods. You can offer your fish frozen fish foods, such as shrimp and silversides, and many Gulpers will accept being hand-fed.

Feeder Fish

Although you can feed your fish live feeder fish, that’s a dangerous practice when given the price you’re likely to pay for your Gulper. Feeder fish often come with an unwelcome cargo of bacterial infections or parasites that could be harmful to your catfish and other tank residents.

That said, if you have a reliable source of healthy, disease-free feeders and high-quality gut-loading food, you might want to consider using common feeder fish such as guppies or goldfish.

This can be a helpful tactic if you need to tempt a wild-caught Gulper to start feeding. Always treat your feeder fish with antiparasitic medication 10 days before feeding them to your Gulper and gut-load the feeders right before use.

What Are Good Tank Mates for Gulper Catfish?

Although they are essentially peaceful fish, Gulper catfish are predatory carnivores that will attempt to eat any fish that’s small enough to fit into their cavernous mouths! For that reason, we recommend that you only add much larger fish to your Gulper catfish setup.

Even so, Gulper catfish are renowned for trying to eat fish that are half as large or larger than they are! That often leads to injured or even dead fish, which is clearly unacceptable.

So, what fish can you safely add to a Gulper catfish tank?

Generally, most hobbyists who keep a community tank with a Gulper catfish aim to have tank mates at least 3 to 4 inches larger than the Gulper cat. For safety’s sake, that size difference must be maintained throughout the Gulper’s life stages.

Some examples of fish species that could do well with Gulpers include:

Gulper catfish are nocturnal, so we recommend that you choose tank mates that are active during the day while the catfish are resting and hiding away.

Can I Keep Gulper Catfish Together?

Unfortunately, catfish are notorious for being aggressive toward their own kind. So, Gulper catfish are best kept as singles. That prevents the fish from becoming territorial and keeps the peace in your tank.

Unsuitable Tank Mates

So, apart from avoiding smaller fish that could be regarded as a food source by the Gulper catfish, you should avoid keeping any fish that might hassle the Gulper.

Generally, aggressive types that might nip at the catfish’s barbels should be avoided. Also, extremely territorial fish species are best avoided. Gulper catfish spend much of the night roaming around the aquarium, and a territorial species might bully the Gulper. However, if you have a very large tank, that might not be a problem.

Finally, bear in mind that Gulper catfish are primarily nocturnal and that behavior might stress a strictly diurnal fish species.

Breeding Gulper Catfish

As there are no reports of hobbyists successfully breeding Gulper catfish in a home aquarium setting, we don’t recommend that you attempt to breed from your fish.

Final Thoughts

Did you enjoy our guide to the weird and wonderful Gulper catfish? If you did, please take a moment to share the article.

Gulper catfish are large, predatory carnivores that should be kept singly or with other large, non-aggressive fish that are too big for the Gulper to try to eat. These nocturnal fish generate a vast quantity of waste, and you’ll need a powerful filter system to cope.

If you fancy keeping one of these amazing catfish, you can expect to spend around $120 on one! The fish are almost impossible to breed successfully in the aquarium, and most specimens are wild-caught.

Do you have a Gulper catfish? Tell us what tank mates work best for you in the comments below.

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