Remember your first pleco? Sure, you got him/her because someone said it’d clean algae for free. He/she was little and could be kept in a bowl. He/she even hid around the glass and he/she looked cute! Fast forward three years and the same fish is now big, glaring at you, making so much waste that it’s stressing your filter.
This is reality versus expectation. The point is to know an adult fish’s size so you can make a proper decision about which fish to get. That graphic I posted is a good start in understanding this. It breaks down the differences. Not all plecos are created equal, not when it comes to their housing requirement.
Why You Must Plan for Your Pleco’s Adult Size
And that’s where things get confusing. I mean, what is a pleco anyway? Well, the term pleco refers to many different types of catfish found in stores. There are dwarves that will never reach more than four inches and there are other fish that will grow past thirty-nine inches. If you treat all those sizes like they’re the same thing, your tanks becomes overcrowded and your fish will suffer.
Take a moment to review chart above. As the size changes, so do their requirements. A Bristlenose pleco may comfortabley live in your average 20 gallon tank. Why? Because it doesn’t get much bigger than four inches.
While a Bristlenose could live in a typical 20 gallon, the same tank wouldn’t accommodate a Royal Pleco. The Royal Pleco grow up to almost eighteen inches in length and requires more than a hundred gallons of space if it is to be mobile. This isn’t just about having enough space to swim around. These bottom dwelling creatures produce large amounts of waste, which means lots of surface area for respiration.
A common mistake by many hobbyists is purchasing larger species and believing they’ll remain small if provided with minimal food. The genetic growth potential of a fish isn’t halted by starving it. It either dies slowly or develops stunted growth which eventually causes organ failure down the road. Plan accordingly for the adult size, not the juvenile in the bag.
That means if you’re planning on keeping a Common Pleco, be prepared to house a twenty-four-inch catfish. This fish produces so much waste that you will need a filter that can process three to five times the tank’s volume every hour. If you don’t have a two-hundred-gallon tank (or an outdoor pond), then don’t get that species. Put it back on the shelf.
Plecos also come in all shapes and sizes, literally! But even more importantly, they have different diets. This further complicates their keeping requirements. As the graphic points out, there are omnivores like the Zebra Pleco who will mostly eat animal-based food (meaty sinking pellets, bloodworms). Then there are herbivores like the Bristlenose which eat algae by scraping it off surfaces.
A carnivore fed veggies only will slowly starve. On the other hand, an algal grazer fed high protein wafers will get digestive issues. Why? Because it doesn’t digest them well. It needs fiber from rotting wood. In fact, its gut bacteria breaks down cellulose to create energy. So you can’t feed all your fish the same thing; no one-size-fits-all diet.
Adding to that are growth timetables. If you have a species of plecostomus, most require several years to fully mature. At two years old, you may think your Common Pleco isn’t so large and only measures out to be ten inches long. But that is just the beginning. He’ll continue to grow and won’t stop until he’s twenty-four inches, with the middle of his second decade having arrived.
By age five, most species will have reached approximately ninety percent of their eventual adult size. At this point, you know how much time you have to change tanks without completely compromising the mobility of your fish. Save yourself some cash and plan ahead. Avoid the day when you realize your fish is too big for its tank.
Long story short, determining which pleco is best for you depends on your commitment and amount of space available. Mini species are recommended for smaller spaces (top part of the size chart). The Pitbull or clown plecos are interesting, active fish without huge setup requirements. On the other hand, if you have more room, the medium and large options can really add something special to how your tank looks and acts.
However, they do require some effort on your part. Provide proper food, cave(s), and strong water movement. And understand, the tiny fry you got in the bag isn’t what they’ll become, it’s just a teaser. Treat them like they’re going to get big from day 1. You need to plan for their adult size so your tank can accommodate them as they grow up.
This way, you don’t end up turning your tank into a cramped cell for an out-of-control resident.
