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Maintaining a fish pond can be a labor of love. There’s something about the serenity and beauty of sunlight refracting off the cool clear water and colorful scales of koi and other pond fish as they swim past plants that’s simply impossible not to love as a fish owner and nature person.
For as much as you might love all of that, however, there’s still the “labor” part of your labor of love to consider. Between the size of the pond, the size and activity of the koi, the sunlight, and all the plants and debris that can accumulate, ponds can get scummy in a hurry.
One way of dealing with that is to get your koi an algae-eating friend in the form of a pleco and plop it into your koi pond as well.
But do pleco get along with koi?
Do they go well with ponds?
If you put them in your pond, what kind of environmental needs do pleco have that should be taken into consideration?
Pleco Fish Relationships
Fish swim and swirl around one another with such ferocious activity it can look like a chemical reaction, and that’s actually a good way to think about fish relationships.
The right grouping of fish can make your aquarium or pond sizzle with excitement, but all it takes is two fish that don’t go together for you to have an explosive disaster on your hands.
Thankfully, koi and pleco typically get along fine. Both plecos and koi are quite hardy, and both have unique color schemes.
What’s more, pleco are suckerfish, so they can suck up a lot of the algae and waste that koi can make, giving them a nice symbiotic relationship. That said, plecos’ mouths are like vacuums, and if a fish is too slow, they may find themselves sucked up along with all the food in their wake.
Koi are typically too big and fast enough that this shouldn’t matter, but if your koi are on the old and slow side, it may be in danger.
A much bigger concern for keeping pleco in your pond is that they require warmer water temperatures than some other pond fish. This should come as no surprise, since plecos are native to South America.
They should not be kept at a temperature lower than 55 degrees Fahrenheit. This is why plecos are much more commonly kept in aquariums rather than ponds.
It’s also why, if you choose to add plecos to your pond you’ll need to make sure it’s warmer than you might otherwise keep it for koi fish.
You may want to add some heaters to make that easier, and adding plecos during the summer is the best way to help get them acclimated.
At the same time, however, you need to make sure that in your quest to make the pond warm enough for plecos you don’t bother the other fish with warmer waters.
Thankfully, koi can handle a wide range of temperatures, with 34 to 90 degrees being best for them. As such, if you’re going to be keeping plecos in your pond, you’ll want that range to trend toward the warmer end.
In the wintertime, you should move your plecos to an aquarium to make sure that they don’t catch cold in sub-50 degree weather.
In fact, 50 degrees is the absolute lowest temperature allowable for your plecos. You don’t want your plecos to feel like they’re on the brink of freezing the whole time, so you should try to keep them at temperatures far above 50 degrees.
If you do put them in your pond, you shouldn’t expect to see them that much. Plecos live by sucking algae and debris, and in so doing they often seek out the underside of rocks or shady areas.
Another thing to keep in mind about plecos is that they can grow quite big – up to 2 ft. In fact, aquarium plecos tend to be a bit smaller than those in ponds or the wild due to the more confined space, so if you put your pleco in your pond, be prepared to deal with a pretty big fish in time.
Make no mistake – a healthy pleco is a fish you should be able to have for some time. Healthy plecos can live for as long as 20 to 30 years, making them a fantastic algae-cleaning investment if you take care of them properly.
On the flip side, transporting a fish that’s as much as 2 ft long back into an aquarium for the winter can be quite a challenge, and needless to say, not one a fishkeeping rookie should undertake.
Plecos can be quite tenacious, and when you have a two 2 ft-long suckerfish trying to wriggle their way out of a transportation aquarium or suck on you for trying to force them into one, things can get challenging, to say the least.
You also need to make sure that the pond itself is big enough for them as well as any koi or other fish you’ll be keeping there, to say nothing of the plants and rocks adorning the water as well.
A 12 ft pleco requires at least 75 gallons when kept in aquariums. That should give you some idea of how much more water a pond-going pleco that can grow to twice that size is going to require.
If you’re going to keep plecos in your pond, therefore, you should make sure that you have the experience and equipment necessary to transport them.
Assessing Water Quality
One of the most important aspects of fishkeeping is maintaining good water quality. Just as you might not want to live somewhere where the air is thick with smoke and smog, a fish isn’t going to want to live in polluted waters where it’s hard to take in clean water through their gills and breathe properly.
In the wild, plecos inhabit high-waterflow areas and waterfalls. Adding some artificial waterfalls and fountains to your pond can, thus, make your pleco feel a bit more at home.
In addition, while plecos suck up a lot of algae, they excrete a lot as well. As such, while plecos can be helpful algae cleaners, you’ll also need to install more cleaning pumps in the pond and change the water more frequently if you have one, especially if it’s a 2 ft-long behemoth.
In terms of water pH, pleco do best at roughly 6.5/7 to 8. Water hardness should be roughly 5 to 19° dH.
While plecos can pose a problem for large slow-moving fish onto which they can attach themselves and start sucking away, plecos tend to be loners. As such, you can place them in your pond and expect them to get along with most other fish.
The big exception to this is their own species.
Plecos are highly territorial, and will defend their territory ferociously against fellow plecos. As you might imagine, when two fish that are 2 ft long become locked in battle, it can be a bloody affair for the combatants, to say nothing of the stress it can cause everyone else in the pond (or yourself as a horrified fish owner).
If you get a pleco for your pond, only get one.
Create Hiding Places
Like many pond and aquarium fish, plecos like having places to hide. These can be instrumental in lowering their stress level.
As mentioned, plecos also like the shady underside of rocks, further fueling their desire for hiding places. A bit of wood, some rocks, or a makeshift cave should do just fine.
Feeding Your Pleco
You might well wonder why there is a separate section for this at all. We’ve already said multiple times that these fish eat algae, so what’s the big mystery here?
Well, the fact of the matter is that while plecos eat algae and debris, that isn’t all they eat, or rather, it isn’t all they should eat.
One great analogy employed by Aquarium Co-Op is to think of your pleco like a pet dog.
On the one hand, dogs are scavengers that will happily gobble whatever scraps you give them. On the other hand, you definitely wouldn’t want that to be all your four-legged friend eats, and the same goes for your pleco pals.
In addition to algae, therefore, you’ll want to try and make sure your pleco has a balanced diet.
What’s more, just as there are different dog breeds, there are different types of plecos and, as discussed below, some are easier to feed and care for in a pond setting than others.
Bloodworms as well as Repashy gel food rank among the most common types of pleco-friendly food. Other favorites include vegetation (so keep that in mind when planting different plants in your pond), driftwood, shrimps and prawns, and protein-rich foodstuffs.
Some owners like to give their plecos algae wafers, though a pond should probably produce enough algae to keep your pleco busy for some time. Again, however, your pleco shouldn’t have to rely on just eating these “scraps” for their whole diet.
Plecos are also nocturnal, so you may want to feed them at dawn or dusk, or other times when the lighting in your pond is nice and dim.
Finally, you should feed your pleco enough food to where they are properly nourished but not so fat as to become unhealthy. Their belly should be slightly round, not a big balloon or shriveled and starved.
Best Plecos for Ponds
While it is possible to keep plecos in ponds, some can make that transition far more easily than others.
Some of the best plecos for ponds include:
- Bristlenose Pleco: These options are by far one of the easiest to breed. They like to eat a lot of vegetables, including cucumber, squash, spinach, zucchini, and even sliced carrots.
- Butterfly Pleco: This species is a bit smaller and a tad more passive and peaceful than other options on this list. It enjoys algae, weeds, worms, and larvae.
- Common Pleco: By far the least high-maintenance option on this list, common plecos are a lot hardier than some of the more tropical variants, and can, thus, better cope with the lower range of pleco-acceptable pond temperatures. They are not picky eaters and can eat everything from algae to crustaceans.
- Clown Pleco: This pleco will require a lot of extra filtration due to the amount of waste it creates. It loves driftwood, so be sure to supply it with plenty of it.
- Royal Pleco: These plecos feature elegant creamy gold striping and are caught in the wild. They are largely nocturnal and have typical vegetation-first pleco eating habits.
- Sailfin Pleco: On the one hand, this is by far one of the hardest plecos to breed given that it is nearly impossible for a non-expert to distinguish between a male and female of the species. On the other hand, the fact they are a little less nocturnal and fine with eating wood and vegetation can make them a bit easier to keep than some of the other plecos on this list.
- Sunshine Pleco: These plecos are peaceful, but have teeth and like to eat shrimp and bloodworms along with algae. They also may have a shorter lifespan than some of the longer-lived options on this list.
- Vampire Pleco: These plecos prefer faster-moving water and are not true vegetarians. In addition to algae, therefore, you’ll need to have some bloodworms and small crustaceans such as prawns or shrimps on hand to keep them well-fed.
- Zebra Pleco: On the one hand, these are magnificent plecos with striking stripes. On the other hand, their natural habitats are now being endangered due to dam construction in Brazil.
Plecos are some of the most popular options for aquarium owners, and so it should come as no surprise that pond owners want in on the action as well.
Thankfully, plecos can work in koi ponds as well as other outdoor fish ponds, provided that the water is warm enough, they have enough space, are given proper hiding spaces and plenty of territory, and you feed them the right foods.