Lots of aquarists keep catfish, but often it’s the same handful of species that seem to be found in most community tanks. Some of that’s down to the retail side of the hobby that likes to stock species it knows sell well. But there’s also a lack of knowledge among hobbyists, many of whom assume that Corydoras catfish are the only small, peaceful catfish suited to community tank life.
In this post we’ll be looking at some of the other choices available to aquarists. Some of these species are mass-produced on farms and routinely traded, others only turn up seasonally when wild-caught specimens are exported from their natural habitat, but there’s nothing on this list that should be difficult to find.
Even though Corydoras aren’t the subject of this article, I am going to start with a trio of pygmy species, Corydoras habrosus, Corydoras hastatus, and Corydoras pygmaeus. Of these, the first is probably the most often seen, being traded as the Salt-and-Pepper Catfish. But all three are very similar in size and habits, which is why they’re worth discussing together.
In short, they’re miniature versions of the Corydoras we known and love, only getting to about an inch (2.5 cm) in length. Apart from their small size, another odd thing about them is that they’re as much midwater fish as bottom-feeders, and if kept alongside other small, peaceful tankmates of similar size they will buzz around the lower level of the aquarium like a swarm of bees. Absolutely charming fish, they are superb additions to planted tanks, particularly when kept in large numbers. Like almost all Corydoras species they are adaptable in terms of water chemistry but do prefer relatively cool water, 72-77˚F (22-25˚C), and as such will work best with other low-end tropical species such as Celestial Pearl Danios and Cherry Shrimps.
Like all catfish, these Corydoras appreciate a soft, sandy substrate. Smooth silica sand is the ideal, and this is sometimes available from garden centres but otherwise traded as pool filter sand. Note that some aquarium sands are abrasive and should be avoided, particularly those sands produced as a byproduct from glass manufacturer, for example Tahitian Moon Sand. When kept in tanks with abrasive sand, catfish often loose the tips of their whiskers, and such damage can be an easy way in for bacterial infections like Finrot.
When it comes to the family Loricariidae, Otocinclus reign supreme in the minds of those aquarists maintaining planted tanks. To their credit, these dwarf suckermouth catfish will consume green algae and are small enough not to damage plants, something that can’t be said for some of the larger suckermouth catfish. But Otocinclus are delicate fish that need relatively cool, very clean water with lots of oxygen and their use in the average community tank cannot be recommended. Most specimens kept in such aquaria end up either starved to death or suffocated by the marginal water quality.
By far the best community tank suckermouth are the various Ancistrus species, often sold as Bristlenose Catfish. They’re medium-sized catfish, typically 5 inches (12 cm) long, and considerably more adaptable than Otocinclus. They aren’t fussy about water chemistry or temperature, and really only expect good water quality and a suitably mixed diet including algae wafers, softened vegetables, and meaty foods such as bloodworms. The most commonly traded species is black with white spots when young but gradually fades to mottled brown as it ages. There are some species that retail their colours throughout their lives though, including L183, Ancistrus dolichopterus, a species that is grey with white spots and sports lovely blue-white edges to its dorsal and tail fins.
Ancistrus are mildly territorial, and each specimen will expect its own cave and about a square foot of space. One of the nicest things about Ancistrus is that they are quite easy to breed, and the males are such good guardians of their eggs and fry that they can even breed successfully in community tanks.
If algae control isn’t a prime motivation, there are a couple of small suckermouth catfish worth considering. The first is Parotocinclus jumbo, a species that gets to about 2 inches/5 cm in length and looks like a metallic grey, robust Otocinclus catfish. Although similar to Otocinclus in looks, these catfish are very different in nature. For a start, they’re quite robust fish that aren’t fussy about water chemistry or temperature, provided extremes are avoided. Not are they good algae eaters, and prefer to consume algae wafers, softened vegetables, and occasionally offerings of meaty foods like bloodworms. They don’t swim about much in midwater, and tend to stay close to rocks, plants and bogwood roots. However, like Otocinclus, they are schooling fish, and shouldn’t be kept in groups of fewer than five specimens.
A second species to think about is the Whiptail Catfish Rineloricaria parva, though other, similar species are traded as well. I can’t say too much in favour of this catfish. It’s very easy to keep, adaptable with regard to water chemistry provided extremes are avoided, does well between 72-79˚F/22-26˚C, and gets along with anything that leaves it alone. They are stick-thin catfish up to about 4 inches/10 cm in length, light brown in colour, and sporting a whip-like extension to the upper lobe of the tail fin that may be almost as long as the catfish itself! Whiptails are mildly territorial but work best kept in groups where their fun social behaviour can be observed. Males are more bristly around the head than the females and tend to shoo each other away from their little territories, while females are more easy going and often group together. Whiptails amble about the tank by walking rather than swimming, sometimes propping themselves up on their pelvic fins. The one thing to remember about them is that they’re carnivores rather than herbivores, and will need to be fed the same sort of diet as loaches and Corydoras.
Historically two transparent catfish were traded as aquarium fish, most commonly an Asian species described as Kryptopterus bicirrhis, and more sporadically an African species listed as Eutropiellus debauwi. In fact it’s questionable that either of these were ever traded much, and the two glass catfish of the hobby were likely completely different species.
In the case of the Asian Glass Catfish, the species seen in shops is Kryptopterus minor, a catfish from Southeast Asia that gets to about 3 inches/8 cm in length. It can do well in soft or moderately hard water, but dislikes excessively warm water, so aim for around 72-79˚C/22-26˚C for best results. In fact despite its fragile appearance this fish is quite hardy and adaptable, and works well in planted community tanks alongside small tetras and rasboras. It likes to rest in shady areas where the water flow is sluggish, but during the night scoots about in stronger water currents hunting for food. Though quite easy to keep, this catfish is highly gregarious and must be kept in groups of at least six specimens; when kept in smaller numbers it is notorious for simply pining away. Feeding can be tricky because these catfish are nocturnal and feed on stuff they find in the water current rather than by hunting along the bottom. Live brine shrimp, daphnia and mosquito larvae are particularly appreciated, as are their wet-frozen substitutes; settled specimens will consume flake food as well, and can be trained to feed during the day instead of at night.
The African Glass Catfish of the hobby is probably Pareutropius buffei, a species that differs from Eutropiellus debauwi (actually, properly called Pareutropius debauwi) by having three black stripes along its body instead of one. In most regards this species is very similar to the Asian Glass Catfish in terms of size and requirements, being a small, gregarious midwater hunter that favours invertebrate prey. It does enjoy strong water currents though, and may be the better choice for a river biotope aquarium.
The most popular African catfish are to be found in the genus Synodontis within the family Mochokidae. While they are all quite similar in shape, they do vary in size and personality, some being small and peaceful, while others much larger and more territorial. On the plus side, they’re all hardy and adaptable, and the big species can hold their own alongside territorial cichlids of similar size.
For aquarists with planted tanks, Synodontis nigriventris is the stand-out species. Sold as the Dwarf Upside-Down Catfish this species only gets to about 3 inches/8 cm in length and has pretty and very variable dark brown and cream squiggles all over its body. Males and females are quite similar in colouration, though the females tend to be slightly bigger and much stockier. Synodontis nigriventris has a reputation for being very shy, but part of that is because it’s too often kept singly; it is a very social species and should be kept in groups of at least three specimens. When kept that way it quickly becomes much bolder and will happily swim about during the day.
Synodontis multipunctatus and Synodontis tanganicae are smallish species native to Lake Tanganyika that work well in hard water communities. While they’re obvious choices for use alongside Tanganyikan cichlids of similar size, they’d also work well with community fish that need similar water conditions, for example Central American livebearers or even Australian rainbowfish. They wouldn’t be so good with most of the Malawian cichlids though, as these tend to be much more aggressive than the Tanganyikan cichlids, particularly the rock-dwelling mbuna.
The Bagridae are a family of Asian catfish species that inhabit lakes, rivers and even estuaries. Most species are quite large, and for that reason their popularity as community fish has been limited, but there are some community tank species worth considering. All are predatory, but they are great opportunists and readily take pellets as well as the usual fresh, wet-frozen and live foods.
At a mere 1.5 inches/4 cm in length, Mystus bimaculatus is one of the smallest of the bagrids and intensely social, so should be kept in a group of five or more specimens. They are pinkish-brown with a black spot behind the gill covers and a second black spot on the base of the tail fin. Their whiskers are extremely long. In the wild this fish comes from very soft and acidic streams and pools, but they are reasonably adaptable and should do well in anything from soft to slightly hard water conditions. The main thing is to ensure excellent water quality: like a lot of blackwater fish, they can be peculiarly sensitive to bacterial infections when water quality is compromised. Given their small size and quite attractive colours, a school of these fish would add a lot of character to a densely planted, shady aquarium with a soft substrate. They are too small to cause much trouble as predators, but will livebearer fry and other bite-sized tankmates.
The Pearl Catfish Mystus armatus is typical of a range of medium-sized species that get imported from time to time. It gets to about 5 inches/12 cm in length and should thrive in any clean, well-oxygenated tropical aquarium of sufficient size. It is basically pinkish-brown in colour with a pearly iridescence and looks particularly good in planted aquaria with bright, open areas where it can swim about freely. Although large enough to eat small fish such as danios, it gets along well with gouramis, medium-sized barbs, and other fish of approximately similar size.
This article does little more than scratch the surface of catfish diversity, it does at least highlight the fact that catfish are a lot more suitable for community tanks and planted tanks than many aquarists suppose. Even if they lack the colours of barbs and tetras, it has to be admitted catfish have lots of personality!