Goldfish like having a little algae in their tank. But they are not an algae eating fish, so it’s quite easy for algae to overrun their tank unless you do a good job keeping it clean.
The unfortunate reality of algae-eating fish is that almost all of them are tropical fish that require a higher temperature than goldfish. This means that you generally cannot have plecos (a tropical fish) and goldfish in the same tank.
However, there are exceptions to this rule – bristlenose plecos and rubber-lipped plecos can live with goldfish. The lower temperature range for plecos is still on the higher side for goldfish, but it’s close enough and plecos are tough enough that it can work.
What Are Rubber-Lipped Plecos?
The rubber-lipped pleco is an uncommon fish in American and European fish tanks. I am not quite sure why as these plecos are just as maintenance free as bristlenose plecos.
Bristlenose and rubber-lipped plecos even look similar.
I suspect it has something to do with breeders only focusing on bristlenose plecos.
Anyway, these plecos thrive in water between 70 and 80 degrees. Goldfish can live in water between 68 and 75 (depending on the type of goldfish).
This makes rubber-lippped plecos the best type of pleco if you want to add some to your goldfish tank.
What Are Bristlenose Plecos?
Bristlenose plecos are the most common type of pleco you will find in a fish tank. They don’t get very large with their maximum height topping off at 5 inches.
Again, perfect for a smaller fish tank or to add with a waste producing machine like a goldfish.
Bristlenoses aren’t nearly as good to put in with goldfish as their rubber-lipped relatives due to the higher temperature that bristlenoses require.
That said, the lower bound of the temperature requirements are much lower than most people are aware – 72 to 80 degrees.
The Benefits of Having Plecos in a Goldfish Tank
Plecos are not super exciting fish. They mostly stay at the bottom of the tank and only really venture out of their hole at nighttime or when some tasty food like zucchini or bloodworms are dropped in the tank.
The main benefit to adding them to a tank is that plecos can eat a considerable amount of algae. They won’t eat enough for you to throw out your algae scrubber, which is good because goldfish need to a little algae.
You definitely don’t have to scrub as much algae off your tank, though.
That’s really the only reason I can think of why you would a pleco in with a goldfish. As I said, the fish aren’t exciting and most people find them a little ugly.
Things to Watch Out For With Plecos and Goldfish Sharing a Tank
Plecos aren’t aggressive to non-plecos, so you don’t have to worry about them chasing around the goldfish.
They mostly ignore other fish and really only get into territorial fights with other plecos.
There are still a few things to be mindful when you have these two fish in the same tank.
You have to closely monitor the water temperature when you have a tropical fish and a goldfish in the same tank. I recommend keeping the temperature in the 70-72 range at all times to ensure maximum health for the plecos and goldfish.
You can sometimes go a little colder just because plecos are a very tough fish. But I would not recommend going much higher than 72 as that will stress the goldfish out a little too much.
Plecos Eat Goldfish Slime
Goldfish have a protective slime that protects them from bacterial infection and other nastiness.
This slime smells very good to plecos for some reason. And they will bite/suck the slime off the goldfish.
Goldfish can very easily get infections when that slime is removed, so I recommend closely monitoring your goldfish for any infections on their skin or scales.
If you notice an infection, then you should separate the fish from each other to prevent further damage.
Ammonia and/or Nitrite Spikes
Goldfish have a reputation in the aquarium industry for producing waste and a lot of it. No other fish produces more waste than goldfish.
Plecos are a close second, though.
You definitely need to do frequent water tests and water changes if you decide to put plecos and goldfish in the same tank.
On that note, you should also have a fairly large tank (70 gallon+) to handle the large bioload from having two types of high bioload fish in your tank.
To summarize, goldfish and certain types of plecos can live in the same tank. Personally, I don’t recommend it even though it’s possible because both types of fish produce a lot of waste and the temperature range is a little low for plecos.
If you do decide to put the two in the same tank, then be prepared for a lot of water changes and vacuuming the substrate. And watch out for the plecos eating all the slime off the scales of your goldfish.