Let's talk about catfish. If you picture a muddy river monster, you're only seeing one tiny slice of a massive, fascinating family. The truth is, breeds of catfish for home aquariums are incredibly diverse. Some are tiny, peaceful cleaners. Others are bold, patterned centerpiece fish. Picking the wrong one can mean a stressed fish, a wrecked tank, or worse. I've kept them for over a decade, and I still see the same mistakes. This guide cuts through the confusion. We'll look at popular picks, hidden gems, and what you really need to know beyond the pet store label. The term "catfish" is a common name bucket for thousands of species in the order Siluriformes. What ties them together? Those famous whiskers, called barbels, used for sensing food and navigating murky water. But here's where the generalization fails miserably. A two-inch Corydoras and a five-foot Redtail Catfish share the name but have zero overlap in care requirements. Most aquarium breeds fall into a few key families: the armored Corydoras, the sucker-mouthed Loricariidae (like Plecos), the nocturnal and often predatory Pimelodidae. Understanding which family your potential fish belongs to is the first step to success. It tells you about its diet, activity level, and potential size. A common error is treating all bottom-dwellers the same. They're not. These are the ones you'll see everywhere. But popularity doesn't always equal suitability. Let's break them down with the details aquarists actually care about. See the range? A Bristlenose is a workhorse. It'll graze on algae, but it also needs sinking wafers and, crucially, a piece of driftwood. The wood isn't decoration; they digest cellulose from it. I've seen too many with sunken bellies because owners thought algae was enough. Corydoras are the puppies of the catfish world. Buying just one or two is cruel. They communicate and feel secure in a group. Watch a shoal of six or more sift through sand together—it's tank life at its best. And about that sand: rough gravel can wear down their delicate barbels, leading to infections. Otocinclus break hearts. They're sold as the ultimate nano algae cleaner. The problem? A new tank often doesn't have enough biofilm and soft algae. They slowly waste away. If you get them, have a plan to supplement with blanched zucchini and specialized foods from day one. Forget just picking the cutest one. Match the fish to your setup. Ask these questions: That "6-inch" Pleco? Many common types (Hypostomus plecostomus) hit 18 inches. They produce waste like a small dog. A 20-gallon tank becomes a toxic puddle fast. Always research the maximum adult size, not the juvenile size in the store. Resources like FishBase or seriously fishkeeping websites are your friend. Pet store info is often simplified or wrong. Catfish compatibility isn't universal. A slow-moving, long-finned Goldfish is a terrible mate for an active, sometimes-nippy Synodontis. Conversely, small Corydoras can be bullied by large, aggressive cichlids. Consider: "Algae eater" is the most misleading label in the hobby. Most are omnivores or carnivores. Bristlenoses need vegetables and protein. Corydoras need sinking pellets they can sift. Many larger species are proficient hunters. You can't just assume your tank's algae will suffice. You'll need to target feed. Once you're past the beginner stage, the world opens up. These breeds offer unique behaviors but demand more specific care. Banjo Catfish: Looks like a dead leaf. It buries itself in the substrate with just its eyes poking out, ambushing worms. Needs fine sand to perform this behavior. Whiptail Catfish (Rineloricaria sp.): Slender, twig-like Loricariids. Peaceful and great for smaller tanks than most Plecos, but they need excellent water quality and calm tank mates. Asian Stone Catfish (Hara jerdoni): Tiny (1 inch), cryptic masters of camouflage. They're for the dedicated observer. Keep them in a species-only nano tank with cool water and lots of leaf litter. You'll spend weeks just trying to find them. I tried keeping a group of Pygmy Corydoras (Corydoras pygmaeus) once. They didn't just stay on the bottom. They'd school in the middle of the water column like tiny tetras, a behavior I never expected from a "bottom feeder." It taught me to never assume.
What's in This Guide?
What Exactly Are Catfish?
Top 5 Most Popular Aquarium Catfish Breeds
Breed (Common Name)
Scientific Name (Genus)
Adult Size
Temperament
Key Care Need Most People Miss
Bristlenose Pleco
Ancistrus
4-6 inches
Peaceful, territorial with own kind
Needs driftwood to rasp on for digestion. Doesn't live on algae alone.
Corydoras (Panda, Bronze, etc.)
Corydoras
1-3 inches
Extremely peaceful, social
Must be kept in groups of 6+. Smooth sand substrate is ideal for barbel health.
Otocinclus
Otocinclus
1-2 inches
Very peaceful, delicate
Requires a mature, algae-rich tank. Often starves in new, "clean" setups.
Synodontis (Featherfin, Upside-Down)
Synodontis
4-10+ inches (varies)
Mostly peaceful, nocturnal
Many species get larger than advertised. Provide caves and dim lighting.
Glass Catfish
Kryptopterus vitreolus
3-4 inches
Peaceful, schooling, sensitive
Needs pristine water and a tight school (5+). Not a beginner fish despite its looks.
How to Choose the Right Catfish for Your Tank
1. How Big Is Your Tank Really?
2. Who Are Its Tank Mates?
3. What Does It Actually Eat?
Beyond the Basics: Unusual & Specialized Species
Your Catfish Questions, Answered
Key Takeaway: Don't shop by the name "catfish." Shop by the specific species or genus name. That "Cool Looking Algae Eater" could be a gentle Otocinclus or a tank-busting Common Pleco. The label rarely tells the whole story.
Do all "algae eaters" actually eat algae?
No, and this is a major point of failure. Fish like the Siamese Algae Eater are dedicated, but many catfish are opportunistic. A Pleco will eat algae, but it's a small part of an adult's diet. They primarily need wood fiber, vegetables (zucchini, cucumber), and protein (shrimp pellets). Relying on them for algae control usually leads to a hungry fish and a still-dirty tank. You clean the tank for them, not the other way around.
Can I keep different breeds of catfish together?
Sometimes, but with big caveats. Avoid mixing species that occupy the exact same niche. Two different Pleco species in a small tank will fight. A bottom-dwelling Corydoras and a mid-water Glass Catfish generally ignore each other. The key is space, hiding spots, and ensuring each species' social needs are met (e.g., Corys in their own group). Overcrowding the bottom layer is a recipe for stress.
What's the best substrate for catfish?
It depends on the breed. For any species that forages with its barbels (Corydoras, many Synodontis), fine, smooth sand is non-negotiable. Sharp gravel causes abrasions and infections. For Plecos that don't sift, gravel is fine, but sand is often easier to keep clean. For burrowers like Banjo Catfish, sand is mandatory.
Why is my catfish always hiding?
For many breeds, this is normal. Nocturnal species (most Synodontis, Raphael Catfish) are biologically programmed to hide during the day. Stress from bright lights, lack of caves, or aggressive tank mates will exacerbate it. Provide adequate hiding places (caves, PVC pipes, dense plants) and use dim lighting. If they're out and active at night under a moonlight LED, they're healthy. If they never come out, even to feed at night, then check water quality and tank mates.
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