Bristlenose Plecostomus

Here's a picture of a young female Bristlenose Plecostomus taken by littleme3333. This little pleco seems to be enjoying her lunch!


The Bristlenose Pleco belongs to the genus Ancistrus. Within that genus, there are about 60 recorded species. Primarily bottom dwellers, don't be surprised to catch the Bristlenose Plecostomus sucking the algae off the sides of your fish tank. They love it. When they've cleaned the algae up, feed them zucchini or algae wafers. I like to steam my zucchini and keep it in the fridge to use as needed.

Here are a few facts to keep in mind if you're thinking about stocking your aquarium with a Bristlenose Plecostomus:

  • Minimum tank size: 30 gallons
  • Easy to care for
  • Adults can reach up to 4" (it varies among Ancistrus species)
  • The Bristlenose Pleco is a peaceful fish (loves to 'chill')

The nice thing about the Bristlenose Plec is that it has a voracious appetite for algae, but won't grow as large as the Plecostomus usually sold at your local pet store. Those can grow as large as one to two feet!

Breeding the Bristlenose Plecostomus is fairly easy, so have plenty of fish loving friends if you're going to try that. Bristlenose have whisker-like appendages around their nose and mouth. It's fun to watch when they flare them out.

The Bristlenose Plecostomus is a great fish tank addition for an aquarium enthusiast looking for a fish that can get a little tank cleaning done. Do you have a favorite Bristlenose Pleco species?

137 thoughts on “Bristlenose Plecostomus”

  1. I think you’d be fine if you add a pleco that doesn’t grow over 4 inches. Gold nugget, or bushy nose plecos are small. If you can find those locally. Give it something to hide in.

  2. Hi there. i lost a whole lot of bristlenose. dont know why. my angels in same tank were ok. i changed water then tried one about 2 months later, it died. I have since pulled everything out and scrubbed and cleaned, though not the gravel. have you ever had this problem. the only thing left i have not changed is my heater. this has a little bit of moisture in it. it doesnt seem to have any electrical problem that i can feel or see??? i need some more bristlenose so if you know Steve from pakuranga who puts his up for sale are you able to send me his email. i note that he used yr photo for a question on trademe and sent a thank you to you. i missed out on the last 2 auctions of his bristlenose as was too busy to go back. thanks Gayle

  3. Gayle,

    I don’t think it’s your gravel. If you had other fish in the same tank, and they were ok, I’m guessing your water parameters were ok? Angels…at least the ones I’ve had have always been the most susceptible to bad water conditions. Are you sure there’s no detergents or other chemicals in your water? Did the plecos have plenty of space? Those are the few things I can think of.


  4. I got a bristlenose pleco a month and a half ago for help with the algae. He seems to have stopped eating it, at first he went crazy and cleaned the sides and some that was growing on the decorations. Does anyone know why he would stop eating it now? I am wondering if when he got a taste of the cory’s wafers he decided he was going to be picky now? Can anyone tell me if they are truely good eagae eaters and what will help control it better?

  5. So i just bout my 2nd pleco, the first one is about 5” long and in with six red belly pirina. now this 2nd one is odd… he is a bristlenose but is a transparent redish-pink and has black spots on him. he is very cute at less than 1” and i was just wondering if anyone had seen any like this before.

  6. I’ve kept fresh water aquariums off and on for about 40 years and generally try to include a pleco for algea control – nothing beats them for this. A few years ago our local water supply was upgraded and all of a sudden I couldn’t keep a pleco alive for more than a week or two. Finally traced it to low pH; our new water treatment plant appears to be removing all buffering capacity – makes for nice soft water but it can be hard on fish; plecos appear particularly sensitive. Anyone with trouble keeping plecos might try monitoring their pH; I test about once a week and anytime it approaches 6.5 I add a quarter tsp of baking soda per 25 gallons. I try to maintain pH just under 7 and the plecos are all thriving.

  7. Hello, I have a 55 gallon tank, I had the tank around 15 years, I have these white specs that look like poppy seeds all over my driftwood, the fish I have are all doing fine, and I never had any problems with the tank before.

  8. hello
    I just bought a pleco. I have a 8 gallon tank with 2 tiger barbs, 4 buenos aires and one pleco? is this too small?

  9. I had 2 40gal and 2 10gal tanks and I moved leaving one of my 40gal.with about 3″of water in it in an empty house with minimal heat (winter) I went back 2 days later to clean out the last tank and found my pleco that I had completely forgotten about. I had caught all my other fish and pack them in zip lock bags so that all arrived in great shape. Pleco’s like to hide and got missed.The Pleco survived the ordeal but he was slow when cold but warmed up and was his old self again.

  10. Hello, I just got my fish yesterday.. I got schooling neon fish and a pleco. He/she seems very passive almost unactive, and the fins are down… I dont know if this is normal behaviour.
    Please help me!

  11. I have a small pleco that I purchased a few months ago and I was told it’s a bristlnose but that they don’t grow their bristles until they get bigger. I’m skeptical as it is already about 2.5-3 inches including tail and there are no bristles. It is dark brown with a pattern on it’s back near the head (like 2 circles). Thanks for your help. I also have a beautiful albino pleco in my other tank. About 6 inches long and I love him!

  12. i have 2 baby plecos… they look healthy. all of sudden they have these brownish spots on there back. i have no clue what it may be. its pretty hard to explain. how can we tell the plecos are sick?

  13. I got a medium pleco about 4 days ago and i read that they like to eat veggies. So I put some brocili in the tank. The only problem is that the pleco isn’t eating it, my fancy guppy is. I don’t know if it is safe for my fancy guppy to be eating it cause after it eats it, it lays on the floor for a long while which it never does. Also, what should I feed my pleco that he will actually eat?

  14. I had my local petshop order in a pair of bristle nose plecs for me. He actually ordered 3 of them. I purchased 2 and my friend purchased the 3rd. These are only little at the moment approx 5cm long and non of them have bristles. Does this mean they are all female or do bristles develop as the plecs get older?

  15. I got 2 of these last week. A male and a female both about 8cm head to tale. I think their awsome, they clean up the leftover fish food and the walls very well. It’s never been this clean. I can’t wait to see them breed and have more of these cute suckers on the glass 🙂

  16. Hello,
    I was wondering if is normal that my pleco is active all day, morning, noon, evening night, I feed him with algae wafers every other day. Is not enough?? I have also a comet fish with him. I use to have a lager gold fish ( he was about 8 in long) but he died. Since then my pleco is more active, it could be another fact??

  17. Yes. Some plecos are that active. Sounds fine to me. I wouldn’t feed any more than that.

  18. Hi. I have a 30 gallon with a male bn and a long fin albino female. Any tips for breeding? I have been trying for mOnths..

  19. I have a bristle nose and today I noticed he is covered in tiny little spots what’s wrong with him??

  20. You’ve described the deadly “ich”. You need to medicate the water with rid-ich as soon as possible.

  21. Hi – my husband has always had a plec in our tank and never had any problems before now. We also have cat fish, clowns, neons, penguins, harlequins, 6-8 plants and a largish piece of driftwood all purchsed from pet stores in a 64 litre tank. We test the ph and ammonia levels on a weekly basis and do a 20% water change also weekly. We have been unsuccessful in keeping a plec alive for more than a few weeks. We usually have a bristlenose around 3cm but have also tried a red spotted who is larger at around 6-7cm. They all have been purchased from pet stores. All start out fairly active and then just sit in one place and stop eating. They get plec wafers and zucchini once or twice a week. All other fish are thriving. Any help with this problem would be gratefully received as we are at our wits end. A tank is not the same without a plec. Thanks

  22. Lyn…

    You’ve had two plecs die? I’d say they were sick when you bought them, or too stressed that they never came out of it. I doubt it’s what you’re doing. Just bad luck. I’ve recently bought two yoyo loaches from a pet store, and then two more striata from another. This was after I tried two loaches a year earlier from another store. Well those first two died soon after, and with my recent purchases, only 1 striata and 1 yoyo are left. They were unfortunately sick when I got them. They llived a month, so I figured they were ok, but no. I knowm it’s not my water parameters, and I’ve been very successful with loaches beforre.

    Try again. You’re doing nothing wrong…sounds like.

  23. Thanks for your response. We will try again, but after losing around 8 plecs this year we are wondering if there is anything else we should be doing. We have bought from 3 different pet stores so would assume they have different suppliers. Did notice on our larger plec a reasonable sized area that looked like an opaque white fungus. This came and went. Our other fish do not appear to have this. Did not look like the dreaded ich. This same tank used to have a plec that grew to around 12 inches. The tank was unused for around two years before we restocked it. All our other fish are thriving.

  24. Hi. I’ve noticed that my Pleco’s underbelly is turning purple and not eating the wafers I put in the tank. Is there a problem? Thanks a bunch! 🙂

  25. I put my bristlenose pleco in a round7 gallon and I was wondering if that was alright cuz I didn’t know. It’s a baby and is about 1.5″ right now

  26. I bought some fish to start filling up a long-empty tank we’ve had, about a month or so ago. I got one pleco and apparently it was female because now we have two baby Plecos, at least I’m hoping that’s all, I haven’t found anymore yet. Does that just mean she was pregnant when I bought her?

  27. Shawn,
    That should be fine. Remember to do water scheduled water changes to keep your fish tank healthy. Mike

  28. Your Pleco sounds stressed. Have you checked water parameters? Is the fish eating? Try putting a cucumber wedge in the tank to see if the fish will eat it. You can weight it down with a fork. Be sure to remove the cucumber if it starts to rot. Also, make sure that your Pleco has plenty of hiding spaces. A Pleco cave would be a good idea if you currently don’t have many hiding spaces.

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