Goldfish are notoriously messy fish, and this often leads to algae problems in their fish tank. Since plecos are such excellent algae eaters, you may be wondering, ‘Can I keep a pleco in my goldfish tank?’.
Well, the answer is yes, but with some conditions to be fulfilled. Only certain types of pleco are suitable algae eaters for goldfish and they also prefer slightly different water parameters, meaning you’ll have to work hard at keeping both species happy. Let’s find out how.
Plecos or plecostomus (Hypostomus Sp.) are a family of suckermouth catfish from South America. This huge genus consists of over 150 species, and only a few of them are suitable for home aquariums.
As some of the best algae eaters, certain plecos make popular additions to community tanks. It must be noted that not all species are very good at eating algae, and some of them grow far too large for the average-sized aquarium!
Goldfish (Carassius auratus) surely need little introduction, but you might be amazed by some interesting facts about them.
Did you know that goldfish are a man-made fish species that was originally bred from dull-looking Asian carp, over 1000 years ago?
Amazingly, some types of goldfish can grow up to more than a foot long and can live for over 40 years.
The Pros of Keeping a Pleco With Goldfish
The main reason that most people would be thinking of adding a pleco to their goldfish tank is that plecos are excellent algae eaters! Most types of pleco will feed on brown algae and green algae, and do a great job at keeping your glass, gravel, and aquarium ornaments free from these types of algae.
Plecos are also relatively peaceful fish and won’t normally interfere with your goldfish. Only on very, very rare occasions would a starving pleco try to feed on your goldfish’s slime coat, and this can be prevented by feeding them with algae wafers if you don’t have enough algae in your tank.
The fact that pleco species grow to a medium-large size is also a positive attribute for goldfish tanks since goldfish can occasionally eat smaller fish in community tanks.
The Cons of Keeping a Pleco With Goldfish
The cons of keeping plecos with goldfish are that goldfish are difficult to find good tank mates for! Because they’re rather messy, cold water fish, most tropical aquarium fish aren’t very good companions for them.
Although some pleco species can tolerate a cooler water temperature, they definitely won’t enjoy the dirty water sometimes associated with goldfish tanks.
Plecos are tropical fish from the fast-flowing rivers and streams of South America and need clean, well-oxygenated water to thrive.
Some plecos, such as the ‘common pleco’ also grow to a very large size, meaning you’d need a very big tank to host one alongside a fully-grown goldfish.
Tank Setup for Goldfish and Plecos
If you want to set up a tank to keep goldfish and plecos together, you’ll need to create a very specific tank environment to keep both species happy:
Goldfish are coldwater fish that prefer a water temperature range of between 60-73°F. Plecos on the other hand are tropical fish that require warm water. Their exact preferences depend on the species.
If you want to accommodate both fish, you’ll need an aquarium heater with the temperature set at 72-73°F for even the hardiest plecos to remain happy.
Goldfish tend to enjoy still water and don’t benefit from strong currents. Plecos, on the other hand, come from rivers and streams and require at least a gentle current to remain healthy.
You can accommodate both species by getting an aquarium filter with a strong flow and directing the output flow toward the bottom of the tank, where the plecos spend most of their time.
Since goldfish prefer to spend their time in the middle to upper water layers they won’t be so affected by the current and can still enjoy a relatively still water environment.
If your existing filter doesn’t have a particularly powerful output, consider adding an airstone, so that your pleco can enjoy well-oxygenated water at the very least.
People are often complacent about tank maintenance when keeping goldfish. Since they’re relatively hardy, some goldfish owners neglect to clean the tank’s filters or make partial water changes often enough.
This simply won’t do for plecos! Since plecos come from relatively pristine waters, you’ll need to maintain the same excellent water quality in your fish tank water for them to thrive. Regular filter cleaning and 15-20% weekly or 30% biweekly partial water changes are essential.
Good aquarium hygiene is also necessary to keep your pleco healthy. Don’t overfeed your fish, and always clean up any fish food that’s left uneaten after a few minutes. Regular gravel vacuuming is also a good idea!
Two Types of Pleco That You Can Keep With Goldfish
Since many types of pleco can grow to enormous sizes, you’d be better off choosing a smaller species of pleco as companions for goldfish, one that can also tolerate cooler water.
Longfin Bristlenose Pleco
- Scientific Name: Ancistrus sp. ‘longfin’
- Water Temperature: 72 – 86°F
- Maximum Size: 4-5 inches
- Average Lifespan: 10 – 15 years
At just 4-5 inches long, bristlenose plecos are one of the most diminutive sub-families of the plecostomus clan and therefore make an excellent choice for most home aquariums.
The longfin bristlenose pleco appears to be more tolerant of colder water temperatures than many of its cousins, which makes it one of the best plecos for goldfish aquariums.
Bristlenoses are excellent algae eaters and are a popular fish with many hobbyists looking for the ultimate algae-eating fish! With their long fins and bizarre whiskers, longfin plecos are also one of the most interesting-looking plecos that will definitely become a focal point in your tank!
Rubber Lip Pleco
- Scientific Name: Chaetostoma milesi
- Water Temperature: 71- 78°F
- Maximum Size: 5-7 inches
- Average Lifespan: 9-12 years
Rubberlip or rubber-lipped plecos grow to a slightly larger adult size than their bristlenose brothers, but with a maximum size of just 7 inches, they’re still relatively small for a pleco!
Like bristlenoses, this species has good tolerance to colder water and should remain happy and healthy with the heater thermostat set to 72-73°F.
Rubberlips have an almost insatiable appetite for algae and do a great job at cleaning glass, gravel, and tank décor. Normally living to around 10 years of age, they’re one of the shortest-living plecos – some of their relatives have survived more than 60 years in captivity!
Other Algae Eaters To Keep With Goldfish
Since plecos need more tank maintenance and excellent water quality to survive, you may be wondering whether some other types of cleaner fish and invertebrates are easier to keep with goldfish.
Nerite snails, mystery snails, hognose cories, and variable platys are all on my list of best algae eaters to keep in a goldfish tank, and you can find out about several other top choices in my article here!
Plecos With Goldfish FAQs
Do Plecos Eat Hair Algae and Blue-green Algae?
Plecos love to eat green algae and brown algae, but don’t tend to be so keen on eating hair algae. Blue-green algae is actually not a true algae at all, but cyanobacteria that tends to grow in poor quality water conditions. There aren’t any fish that will eat blue-green algae!
Better algae eaters for hair algae are aquatic snails and amano shrimp. As for blue-green algae, a few species of snail will eat it, but your best way to get rid of it in the long term is to substantially improve your water quality!
Will Plecos Eat Goldfish Food?
Plecos are omnivorous fish that will eat just about any kind of fish food that falls to the bottom of the tank, including goldfish pellets and flakes. If your pleco is especially hungry, he may eagerly sniff out fish food that’s fallen onto the gravel and eat it up quickly – that’s why some people call them part of the ‘clean up crew’!
If any fish food is left for more than a few minutes, however, it may start breaking down and contaminate the water. To keep your water quality high, remove any food that’s not eaten within a few minutes.
It’s possible for goldfish and plecos to live together in the same aquarium, but you’ll need to work at making tank conditions suitable for both species and also choose the right type of pleco.
Fulfilling both of these species’ needs for water temperature, water current, and water quality, it’s possible that they could live together for years to come.
To find out about other types of goldfish tank mates that eat algae, don’t forget to check out my dedicated article here.