Most people start looking into “pet catfish” when they’ve noticed bare patches of food on the substrate, algae creeping in, or a quiet tank that could use a bit more movement. Catfish can help, but they also change the rhythm of an aquarium: they add bioload, they need the right floor space, and some species quietly outgrow the tank you first imagined.
Below is a practical guide to choosing common aquarium catfish in Australia, setting up a tank that suits their bodies and behaviour, and avoiding the usual problems—poor water quality, damaged barbels, and mismatched tank mates—before they start.
Catfish in home aquariums: what they are (and what they’re not)
“Catfish” is a broad name for many fish groups, most of them freshwater, that share the familiar whisker-like barbels around the mouth. Those barbels are packed with touch and chemical sensors and help the fish find food, especially in dim water or over sand and leaf litter.6
In an aquarium, many catfish spend long stretches close to the bottom, moving in short, deliberate bursts between shaded cover and open feeding areas. Some are gentle shoalers, some are solitary, and a few are active hunters that do best in larger, calmer communities.
A quick reality check before you buy
- Tank footprint matters more than litres. Bottom-dwellers need floor space, not height.
- They are not “clean-up crews”. Catfish still need a proper diet, and they still produce waste—often a lot of it.
- Species names are everything. “Catfish” in a shop label can mean a small Corydoras, a fast-swimming pictus, or a species that will reach dinner-plate size.
- Check legality and don’t release fish. In NSW, releasing aquarium fish to public waters is illegal, and prohibited species rules apply; unwanted fish should be rehomed responsibly.4
Common pet catfish (and what they actually need)
Corydoras (cory cats)
Corydoras are small, peaceful bottom-dwellers and one of the best “first catfish” choices for a community tank. They are social and generally do best in a proper group (often recommended as six or more of the same species), where they spend more time foraging openly instead of hiding.7
What tends to suit them:
- Substrate: fine sand or smooth, rounded gravel to protect barbels.
- Layout: shaded edges, driftwood, plants, and open feeding lanes.
- Temperament: best with calm, non-nippy tank mates.
Pictus catfish (Pimelodus pictus)
Pictus catfish are often sold as “community catfish”, but their needs are closer to an athletic river fish: they are fast, nocturnal, and need room to cruise. Many care guides recommend a tank in the 55–75 gallon range (or larger for groups), plus strong filtration and excellent oxygenation.8, 9
Two common surprises with pictus:
- Space: they can become stressed in smaller tanks because they are constant swimmers.8, 9
- Tank mates: small fish can be at risk, especially at night, because pictus have a large mouth for their size.10
If you want a relaxed, slow-moving community tank, a pictus is usually the wrong shape of fish for it.
Benefits and drawbacks of keeping catfish
Why people love them
- Bottom-level activity: they use parts of the tank other fish ignore.
- Natural behaviours: foraging, sifting, and exploring cover can be quietly fascinating to watch.
- Often hardy when water quality is stable: many common species cope well once the aquarium is properly cycled and maintained.1, 2
What catches people out
- Bioload: more waste means more filtration capacity and more consistent water changes.1, 2
- Outgrowing the plan: some “cute” juveniles become large, long-lived fish (and some species can live for decades).3
- Nocturnal habits: several catfish are most active in low light, which can make them seem “missing” during the day.
How to set up a suitable aquarium for catfish
Start with the fish’s adult size and behaviour, then build the tank around that.
Tank size (practical guidance)
There isn’t one universal “catfish minimum”, because the group ranges from tiny Corydoras to large-bodied species. As a starting point:
- Small Corydoras groups: prioritise floor space, stable filtration, and safe substrate.
- Pictus catfish: plan for a larger tank (often 55–75 gallons or more), with swimming room and strong filtration.8, 9
If you’re choosing between two tank sizes, pick the larger footprint. It gives you more stable water chemistry and a calmer fish.
Filtration, cycling, and oxygen
Most problems with aquarium fish trace back to invisible chemistry: ammonia and nitrite rising in a new tank, or creeping up in an overstocked one. A mature biological filter is the engine that keeps those toxins in check, and it typically takes weeks to establish in a new aquarium.1
For tropical aquariums, routine testing for ammonia, nitrite, and nitrate is part of normal care, not an optional extra—especially after changes to stocking, feeding, or filtration.2
Aeration matters as well. Beneficial filter bacteria and fish both rely on oxygen, and many active catfish do best with good surface movement and well-oxygenated water.1
Substrate and décor (protecting barbels)
Barbels are working tools. Rough gravel, sharp décor, and chronically poor water quality can damage them over time. Choose sand or smooth substrate, keep the tank clean, and use driftwood, caves, and plants to create shaded cover and clear paths for foraging.
Lighting
Many catfish prefer subdued light. You don’t need a dark tank, but floating plants, driftwood shadows, and gentle transitions between bright and dim areas can make them more willing to feed and explore.
Feeding and nutrition in captivity
Most commonly kept aquarium catfish are omnivores or opportunistic feeders. In the wild, many eat insects, small crustaceans, worms, and plant material, picking through substrate and debris as they go.
A steady, sensible approach in a home aquarium:
- Base diet: quality sinking pellets or wafers.
- Variety: supplement with frozen foods (such as bloodworms or brine shrimp) and occasional fresh options suited to your species.
- Timing: for nocturnal fish, feed near lights-out so food reaches the bottom before daytime fish take it.
- Moderation: overfeeding is one of the quickest ways to spoil water quality, particularly in smaller tanks.1, 2
Common health issues (and how to prevent them)
Catfish are often described as “hardy”, but their health is closely tied to water quality. Stress from ammonia, nitrite, unstable temperature, or crowding can leave fish more vulnerable to infection and parasites.1, 2
Early warning signs worth taking seriously
- reduced appetite
- unusual hiding, lethargy, or frantic darting
- hanging near high-flow areas or the surface
- damaged barbels, reddened patches, or frayed fins
Prevention that actually works
- Keep ammonia and nitrite at zero in a cycled aquarium, and manage nitrate with regular water changes.1, 2
- Quarantine new fish where possible, to reduce disease introduction.
- Avoid overcrowding and sudden changes to feeding or filtration.
If fish are unwell, treat water quality first, then seek species-appropriate veterinary or aquatics advice before adding medications—some catfish can be sensitive to certain treatments.
Breeding catfish in captivity (a realistic view)
Some catfish, especially certain Corydoras species, may breed in a well-kept home aquarium with good conditioning and stable water changes. Others, such as pictus catfish, are rarely bred successfully in home setups and may require conditions that are difficult to replicate without specialised facilities.11
If breeding is your goal, choose a species known to breed in aquariums, then research that species specifically—spawning triggers and fry foods vary widely across “catfish”.
Interesting facts (and a few myths)
“Whiskers” that can taste the water
Those whiskers are barbels, and in many catfish they are loaded with sensory cells used to locate food, especially in low visibility. In some species, chemical sensing is so important that it outweighs vision.6
Do catfish make sounds?
Yes—many catfish can produce sounds, commonly through pectoral fin spines (stridulation) or by using the swim bladder as a resonating chamber. It’s not a myth, though you may not hear it over pumps and filters.6
Final thoughts
A well-chosen catfish adds a steady, grounded presence to an aquarium—something that moves through shade and sand while the rest of the tank flickers above. The best outcomes come from matching species to space, keeping water quality stable, and treating barbels and bottom space as essential habitat, not decoration.
References
- RSPCA Knowledgebase: Why is water quality important when setting up a fish aquarium?
- RSPCA Knowledgebase: How should I care for my tropical fish?
- NSW Department of Primary Industries: Aquarium owners and trade
- NSW Department of Primary Industries: Caring for your pet fish
- NSW Department of Primary Industries: Monitoring ammonia
- Wikipedia: Catfish (overview of barbels/chemoreception and sound production mechanisms, with cited sources)
- Aquarium Care Basics: Cory Catfish (schooling behaviour and general care)
- WebMD Pets: What to know about pictus catfish
- Aquariadise: Pictus catfish (Pimelodus pictus) care sheet
- RSPCA (UK): Choosing an aquarium for pet fish (filters, cycling, ammonia and nitrite)
- Aqua-Fish: Pictus catfish (Pimelodus pictus) care guide (notes on breeding rarity in home aquaria)
Veterinary Advisor, Veterinarian London Area, United Kingdom