WILL THE REAL PLECO PLEASE STAND UP?
It might be the best known catfish in the industry, and the chances are you’ve never met the real thing. Just who is the Common pleco?
It might be the best known catfish in the industry, but the chances are you’ve never even met the real thing.
EVEN IF you’ve only been in the hobby for just a few months, the word ‘pleco’ will likely conjure up an image of a friendly, neighbourhood suckermouth catfish. More so, your idea of a common pleco is probably that of a generic mottled-brown sucker that can be found in almost any store at any given time. They’ve been an aquarium staple for generations, which in itself is baffling considering how unsuited these animals are for the majority of home aquaria. Nonetheless they’ve maintained popularity the world over, to the point that aquarium populations have now spilled over into nonnative ecosystems. Despite being one of the best-known fish in the hobby, some confusion remains regarding the identity of our common catfish. So who are they?
Hypostomus plecostomus, the name-giver
Hypostomus plecostomus is the species to thank for the ‘pleco’ moniker we use everyday, and indeed, this is the scientific name you may see pasted on to an ubiquitous ‘Common pleco’ label in stores. However, Hypostomus
plecostomus is not as common a pleco as many sources would have you believe. H. plecostomus may appear similar to what you might picture the common pleco to look like, but in reality this species is scarce in the aquarium trade. Originating from north-eastern South America, there is a spotty record of these animals arriving from their home waters into the tanks of wholesalers and aquarium dealers. Back when they first popped up, they went by another name: Plecostomus plecostomus. A name so nice they used it twice, and it would seem that dealers took to using this name for both the original
P. plecostomus as well as any of the other similar-looking suckermouth catfishes that arrived.
Even though the original
Plecostomus didn’t seem to gain favour with hobbyists, the suckermouth catfishes that remained held onto the name, something which has perpetuated to this day. To keep it simple, the named was chopped to ‘Pleco’ somewhere down the line. So who are the ‘Common plecos’ that we’re seeing around today?
Nine times out of ten, they’re one of a handful of species of
Pterygoplichthys, with P. disjunctivus and P. pardalis being the most commonly traded, alongside a few others that make regular appearances. Hybrids between these species might be as common as any of the parent species, bearing a mixture of characteristics somewhere between what you’d expect to see in the parents.
The genus Pterygoplichthys and its members have gone through more name changes than I think many would take the time to suss out. But, given that they’re all superficially lookalikes and commonly available, it doesn’t take much imagination to see how they got stuck with the ‘Common pleco’ moniker.
Despite incorrectly sharing names,
Hypostomus plecostomus can be differentiated from our popular
Pterygoplichthys by a few characteristics - Pterygoplichthys have ten or more dorsal fin rays, whereas Hypostomus have fewer
than ten. Hypostomus plecostomus proper has a rather limited range and likely doesn’t get exported often, so odds are most common plecos, as labelled, will be one of the Pterygoplichthys.
In the grand scheme of things, these animals are not awfully different. They’re outwardly similar and could easily be confused at a glance — there are many examples among both
Hypostomus and Pterygoplichthys that could be briefly described as ‘brown with a smattering of darker spots’. Many of these share similar diets and ecologies, and by extension their captive care is remarkably similar, too.
Why so common?
Regardless of the identity, we’re still talking about a group of similar fish that regularly reach over 20 to 25cm (8 to 10 inches), are notable poop machines, and despite assurances from many sales folk, does not really care much for your algal overgrowth or cleanliness problems.
So how did they become a staple aquarium fish? I’ll wager that it’s the perpetuated myth that these animals are steadfast cleaners that props them up somewhat. There’s good reason so many newcomers instantly associate a plec of any description with being a ‘suckycleany’ fish. Besides, for the unscrupulous dealer the pleco represents an easy sell to an inexperienced fishkeeper who would happily hand over some of the cleaning chores to their pets. This demand is satisfied with a relative ease of production on fish farms in the United States and Asia, which together seem to meet a worldwide demand at a reasonable cost. Eventually this fish, probably now a monster in size and not performing cleaning tasks as promised, is left in the hands of a bewildered, if uniformed, newer hobbyist.
In the best case scenario, the keeper will look for a larger tank to accommodate their pet, learning to love these dull, unassuming brutes for who they are.
Not everyone is capable of upgrading their system, though. The next avenue is trying to pass the animal on to more suitable accommodations. Online forums, social media and pet stores are all familiar with larger plecos looking to be passed on. More than a few retailers readily turn such offers away — it’s rather difficult to sell a pleco that size, and the prospect of holding an enormous fish that may take months to rehome is not a welcome one. From a business perspective, it simply takes up valuable space and resources.
The public aquarium world, too, is flooded with offers. It isn’t the role of public aquaria to accommodate unwanted pets, and even if they do graciously offer homes to a few specimens, ultimately they’re going to run out of hospitality. Even big display tanks aren’t bottomless pits. This unfortunately has led to another, far more damaging choice that some fishkeepers make: releasing their animal into the wild. Perhaps thought of as an act of mercy, a mishmash of feral plecos have made new homes in more than twenty countries around the world, having established in many of the warmer regions where they persist to this day. At first glance, these catfish probably don’t seem to be a menacing alien; they do however pose a number of threats to aquatic ecosystems.
In the absence of natural predators, plecos can absolutely overwhelm these ecosystems. These booming populations rapidly consume resources; even when feeding on their natural diet, these fishes can become direct competition to native fishes that utilize the same food items. These resources are quickly depleted once the population reaches a certain size. From there, opportunistic feeding on invertebrates, plants and eggs can further destabilise ecosystem functioning.
Then there’s the physical
damage. Pterygoplicthys like to excavate deep nests from river banks, in which they reproduce and avoid predators. Over time this erosion can alter the very dynamics of the rivers they infest.
Better alternatives
Algal annoyances are best addressed from the root of the problem, rather than dealing with the resultant algal issue. In most cases, algae bloom in the presence of excess light and nutrients, or take hold when maintenance has been shrugged off for a little too long. Fixing these may eliminate the need for you to add a biological control agent, as well as improving the overall health of your tank.
The outdated idea of ‘clean-up animals’ needs to die off, too.
Fishes under our care should be accommodated appropriately rather than left to deal with the scraps of other fishes. Loricariids (suckermouth catfish) in particular benefit from regular feedings that better represent their natural browsing behaviour. Being relegated to the leftovers of unspecialised diets from other fish can cause harm in the long term.
Scooting past all of the above, you still might have it in your heart to bring a little sucker into your life. I can’t blame you — they occupy a unique place in the aquarium and have their own charms. Fortunately there are several far better options to wade through.
My pitch to you are the smaller loricariids, like Otocinclus and
Ancistrus bristlenoses, which make better choices for most home aquaria owing to their smaller sizes and community compatibility. There are a number of species in these genera that are regularly available at affordable prices, without the worry of outgrowing your aquarium. In the case of Ancistrus you can enjoy the experience of breeding a fish with minimal effort, and will certainly find little to no difficulty in rehoming the offspring of these well-loved fish.