Bristlenose Pleco – The Care, Feeding and Breeding of Bristlenose Plecos

Bristlenose PlecoQuick Stats

Minimum Tank Size: 29 Gallons
Care Level: Easy
Water Conditions: 6.5 – 7.5 and Soft to Medium but is highly adaptable
Temperature: 70-80 F (20-27 C)
Maximum Size: 6 inches (15 cm)

The bristlenose pleco (Ancistrus cirrhosus), also known as the bushynose pleco, has a wide distribution throughout the Amazon river basin in South America. It can be found in a variety of habitats, from shallow low oxygen floodplains, to the deep, dark waters of rivers. There are several commercially available species, but Ancistrus cirrhosus is the most common.

Bristlenose plecos are commonly known as suckerfish, and make an excellent addition to most freshwater aquariums. They are arguably the best algae eaters available – both because of the large amount of algae that they consume and their hardy, easy to care for nature.

While the common pleco can grow to the size of a river monster in a tropical aquarium, bristlenose plecos stay quite a bit smaller, and usually top out at around 6 inches. Because of this, they are a far better choice than the common pleco if you are looking for an algae eating fish.


Bristlenose plecos need a spacious tank with strong filtration. The reasons for this are simple – they need space, and they tend to be prolific poopers. Much of their life seems to consist of searching for food, eating the food, and then searching for more. Because of this, they are prodigious poop producers, and if the water isn’t well filtered, the water quality will quickly plummet.

In the wild, adult bristlenose plecos tend to hide in caves and under driftwood when they aren’t foraging and should be provided with similar hiding places in the aquarium. This can be as simple as providing a clay pot on its side, or you can provide large pieces of driftwood with overhangs that a bristlenose pleco can hide under.

When choosing a filter for them, a HOB (hang-on-back) filter is the most economical choice, and in combination with a sponge filter, it will keep the water sparkling clean . However, if you have a bit more money to spend, a canister filter is usually the best choice for most tropical aquariums.

I would strongly recommend choosing an Aquaclear Power Filter for a bristlenose pleco tank. This filter combines excellent filtration with a durable design, and it will keep your tank sparkling clear for years to come. You can also read the Aquarium Tidings Aquaclear Filter Review here.


Like previously stated, bristlenose plecos love to eat and you can provide them with a wide range of food. Their main diet should be composed of a spirulina based sinking pellet, since they tend to mainly eat on the bottom of the tank. This should be supplemented with vegetables, as they need a large amount of plant matter in their diet. A hungry bristlenose pleco will completely devour every last piece of blanched zucchini, cucumber medallions and shelled peas. They also appreciate broccoli and a wide range of other vegetables. Always remember to remove any uneaten vegetables after 24 hours to prevent water fouling.

If you are hoping to get a bristlenose pleco into breeding condition, they should be fed live or frozen foods. Their particular favorites are bloodworms and live blackworms, and they tend to ignore most other frozen and live foods. The key is to ensure that the food reaches the bottom of the aquarium, or they most likely won’t even notice it.

One thing to remember with bristlenose plecos, is that they require fiber in their diet- especially if they are consistently fed regular fish food. Some fiber can be provided through vegetables, but unless you are careful to consistently feed vegetables, they generally won’t have enough fiber in their diet to remain healthy.

There is a simple solution to providing enough fiber – just include a piece of driftwood in their tank. Nearly all species of plecos will rasp on any driftwood in their tanks, which provide them with more than enough fiber to help them stay healthy and active.

bn plecoBreeding

Bristlenose plecos are easy to breed and only usually have to be provided with a cave to spawn in – the rest they do on their own. You should always try to have more females than males, unless you have a very large tank. The males are incredibly territorial and will quickly claim a cave for breeding purposes. Any other males will then fight the male for control of the cave and given the opportunity, will indulge in quick meal of caviar (they will eat their male rival eggs).

When preparing to breed bristlenose plecos, you first need to determine if you have at least one male and female. You can determine the sex of them by simply looking at the “bristles” on their heads. Males will usually have larger bristles and they will extend to the middle of its head. Females will only have bristles around their mouth, and they tend to be much smaller than the males.

When the male is ready to breed, it will begin to excavate a cave (clay pot or overhang), and will clean off the surfaces of it in preparation for eggs. Once the male is done, he will settle in to his newly claimed cave, and wait for a female. Once a female comes by, she will inspect the cave and if suitably impressed, will decide to move into the cave and deposit her eggs.

Once the eggs have been deposited on the walls of the cave and fertilized by the male, he will push the female out the cave, and begin to guard the eggs. During this time, other females may be enticed into the cave, and the male may end up fertilizing the eggs from several different females.

The eggs will then hatch after around 4-10 days and the fry will cling to the sides of the cave until they have completely absorbed the egg sacks. During this time, the male will continue to guard the fry until they are free swimming on their own.

The fry can be feed with infusoria or powdered spirulina. After a few days they can be fed baby brine shrimp and they will also eat any available algae.

Pleco or Plecostomus?

If you are new to the hobby, you will only ever rarely hear “plecos” referred to as a plecostomus. There is a simple reason for this – it’s considered bad luck to refer to plecos by their full name. There is a belief among some in the fish keeping hobby, that if you use the full name, you will soon have a dead pleco. (I will update this page if I suffer any devastating pleco losses after daring to say plecostomus in this article.)


  1. says

    Hi there,
    I have a few questions…

    How do they mate together ?
    How long are they pregnant for ?
    As today’s date is the 14th October, how many times does it get pregnant for. ?

    • says

      They don’t get pregnant but a male bristlenose pleco will entice a female bristlenose pleco into a flower pot or cave where she will lay her eggs and he will fertilize them. The eggs are then cared for by the male until they hatch in a few days. The fry will then become free swimming a few days after that.

      This can happen relatively regularly if you provide them with good food and conditions.

  2. barbara says

    How do I get my bn to stay out of hiding long enough for me to get a good look at his bristles? He’s quickly back in hiding. I’d like to get him/her a mate, but the wrong choice could be disastrous. I put algae wafers in, and cucumber/ courgette or whatever.

    • says

      It can be very difficult to get some plecos out of hiding. If you remain completely motionless after adding food, it will often come out so it can be examined. Barring that, you can use a flashlight after you turn the lights out in the room, and you can often get a good look at it that way. I’ve used that method with some of the other nocturnal fish that I have.

  3. callum says

    I lost 2 plecos the last 2 days after saying their full name a week ago…

    But today i have just found 12 babies!!! :D

    • says

      Take care of those babies. They can make up for you saying the full name. lol

      I know it’s a silly superstition, but years ago I said the full name and a 12 inch pleco somehow escaped my main tank and died on the floor. I haven’t said it since.

  4. Robert says

    I got 4 plecos in July as barely half an inch long so I’m guessing not very old. But how old do they generally have to be to start breeding?

    • says

      I wouldn’t go by age, since so many factors can affect their maturity. I would go by size, and most bristlenose plecos will begin to breed when they are around 3-4 inches in length. Four inches seems to be the more common size though.

  5. Anne says

    Hello, what a fabulous no-trivial-trimmings-article, thank you!

    So, I now have a 4cm fit & healthy regular bristlenose pleco. Alone in his 110L tank, Juwel sophisticated filtration system, PH 7.5, Ammonia reading 0, 26 degrees C; I have decided to stick to this type of fish only and I do not want to overpopulate, but I think he needs at least one little friend.
    My preference would be an albino pleco for variety, which I am finding difficult to source… I’m in the southwest of UK.

    There are two things I really need to know:
    1) Am I right to think I should only add one more fish? Or would three BN plecos be happy & healthy in 110L?
    2) How old / what size does a BN pleco develop its bristles so it can be recognized as male or female?

    I just want a couple of happy pet fish, no intention to breed them, definitely don’t want to see them fight…

    Thanks in advance for any advice :)

    • says

      I’m glad that you enjoyed the article. And bristlenose plecos are perfectly happy being solitary creatures. Males establish large territories, and will often fight with other males – especially in a smaller tank like the on that you have. You may be able to keep three adult bn plecos in your tank, but you have to be sure that the tank contains only one male. Also, when males are younger they are known to attack female plecos. It’s best to make sure that all of the fish are mature before keeping them together. While juvenile females are often attacked, the presence of an adult female seems to change their behaviour, and you generally only get some chasing.

      Also, in my experience the bristles begin to show on males usually when they are between 4-6cm in length. They can take a while to grow in, and the females don’t develop much in the way of bristles.

      I hope this helps.

      • Anne says

        Yes, it does help, thank you! Since loneliness is not an issue, I shall patiently wait till my pleco is mature to be sure of its gender. :)

  6. Mike says

    I’ve recently discovered that my bristlenose plecos have laid eggs inside of a piece of driftwood. I’m really excited to have the babies to care for. I was curious to know if keeping them inside the tank I currently have is ideal since they are weak and still new, or if setting up a 10 gallon tank with water and rocks from this one would be helpful to keep them isolated. They are currently in a 35 gallon with a couple other plecos and some angels. I’d like to hear your opinion on the matter. Thanks in advance

    • says

      It’s a tough decision to make whether to keep them in a community tank, or to remove them to their own tank. The problem is that it is very easy to injure or kill fry when transporting them from one tank to the other. Not only is netting out of the question, but any change in their water chemistry is likely to kill them. But on the other hand, very few generally survive in a community tank, and you will likely see most of your bristlenose pleco fry get eaten over time.

      If you do decide to move then, you will need to move them with something like a turkey baster. Using a net is just too danger with new born fry. And then the 10 gallon tank must be fully cycled – any spike in ammonia,nitrites or even nitrates will most likely wipe out the fry. Then before you place them in the tank, you will have to use the drip acclimatization method to ensure that they have plenty of time to get used to the new water chemistry. It’s difficult to do, but not impossible.

      • Mike says

        As a follow up, I did move all the eggs to a new tank. I took the whole piece of driftwood that they were in, father and all, kept it submerged for most of the transfer and they did just fine. They hatched 11/04 and I have over 80 healthy plecos. I’m going to be selling off nearly all to a local fish store but I’m having a lot of fun watching them grow and develop. Thanks for the help

  7. Ryan says

    I have a nice pair of BN and they have breed like crazy and if Plecos shouldnt be counted as a swimming fish more like an ornament then how many are ok to keep in a 40 gal tank i have well over a hundred that are a quarter inch 10mm long and everything seems ok the water is pristine and I have about 12 pieces of driftwood in it. they live on frozen fish food cubes and veggies

    • says

      The problem that you run into with bn plecos, is that the males stake out large territories and defend them vigorously. This isn’t much of a problem while they are young, but as soon as they begin to grow you’ll have some major aggression issues on your hands. For a 40 gallon tank, you should be able to get away with two to three bristle nose pleco males, and about twice that number of females. Any more than that, and you’re just asking for trouble.

  8. marie says

    Hi what do baby bn feed on as think I may have some soon when do the male bn level them on their own very new breeder

    • says

      You have a few options with bn pleco fry. You can provide rocks with lots of algae for them graze on, or you can provide powdered spirulina. They will also feed on vegetables, so you can drop a few at different places in your aquarium, but any uneaten pieces will have to be removed within 24 hours to prevent the water from fouling. Some people also provide them with baby brine shrimp, though in my experience they will be fine with some spirulina algae wafers broken up into their tank.

  9. Wanda Dority says

    Thank you so much for your article. We have a 50 gallon tank with two adult bn plecos. We were quite surprised when they laid eggs. I read all I could find, but none were specific to bn plecos. Our first batch of babies were all eaten by our angels and swordtails. Two months later they hatched out more eggs and per info I found on the web we did almost 50% water changes and they all died in one day. Seven or eight weeks later we had another batch of babies. I built a divider with a frame and plastic canvas to keep the other fish from eating them. Some got past the barrier and were eaten, but we have about 24 that are 1/2″ to 3/4″ long. Now, six weeks later we have another batch of babies. Looks to be 40+.
    You mentioned that young males will attack young females. Can they all be left together until they are ready to sell or do I need to separate them? How big might they be when I need to separate them? I had thought about moving the adult female to another tank to delay any more eggs being laid. If I understood you correctly, you said the presence of an adult female would help reduce the aggression.

    • says

      That’s great that you were successful in raising some bristlenose pleco fry.

      And most can be left together (assuming your aquarium can handle the waste load) until they reach about an inch in length. After that, you will start to experience some pretty serious aggression issues. A lot depends on the set up of your tank though. If you have a lot of plants, driftwoods, or ornaments that help to establish little territories, you should be able to get by without too many issues. If they’re all crammed together, you’ll end up with some fish with shredded fins.

      The best thing to do is to keep an eyes of them. Most stores will only buy them once they reach 1.5 inches in length, so the challenge is to have enough grow out tanks to accommodate all of the bn pleco fry.

  10. marie says

    will to night I have just seen some baby b n just like to know if I can do a tank clean up or not what the right food for babies as new to fish keeping

  11. Mykal says

    I have a small clutch of baby bn and was just wondering how big before I can move them into anther tank?? There around an inch long at the moment

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