Bristlenose Pleco Size—How Big Do Bristlenose Grow?

Bristlenose Pleco Size—How Big Do Bristlenose Grow?

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Of all bottom-dwelling fish kept by hobbyist, bristlenose pleco are some of the smallest species, which makes them ideal for beginners aquarist with tiny starter tanks.

But this does not mean they can only be kept by people without much experience or small tanks, definitely not.

Even seasoned aquarists with bigger tanks can maintain them, especially, where they need algae-eaters.

Bristlenose pleco make an ideal alternative for big algae-eating fish like Siamese and Chinese algae eaters, particularly in aquariums, stocked almost to the maximum.

Overall, bristlenose plecos kept in home aquariums grow to between 3 and 6 inches, with even the biggest fish maxing out at 6'5 inches. As such, they will go in a tank even as little as 20 gallons, though 30 gallons is recommended.

Below I’ve discussed in a little more detail, the average size of bristlenose plecos and how to maintain them. Please read on.

Bristlenose Pleco Growth Rate

Over and above their small size, bristlenose plecos are also easy to maintain and breed in captivity.

You only need to keep a breeding pair together and provide them with a cave and food, and they will do the rest on their own. A lot of plants are highly recommended to replicate their wild environment in the Amazon river basin.

The life of a bristlenose pleco begins when the eggs hatch.

Usually, the fry will feed on the egg sac for the first few hours to days of their life, then slowly move on to feeding on soft vegetables like cucumber.

When the bristlenose pleco babies reach to between 2 and 3 inches at 6 months or so, they usually are ready to breed. At this point, males will have developed bristles and also tend to a little bigger as they grow faster than females.

Once you’ve successfully sexed them and they start breeding (at 6 months to a year), your bushy noses will continue to grow for another 1.5 years, reaching their full body size within 2 years.

After two years (or so) they’ll stop growing, but this does not mean that your fish is nearing its death, bristlenose pleco can live for up to 10 years in a fish tank if maintained in the right conditions.

Bristlenose Pleco Fry Growth Rate

Compared to other fish fry, bristlenose pleco babies do grow at a somewhat slower rate, so some patience is advised. Even so, once they reach the six months mark, they tend to develop at a faster-rate.

Males also tend to develop faster than females, albeit the difference not being too apparent in fry.

Also note that fry from the same brood don’t always grow at the same rate. Some will lag and only pick up after three or four months after the eggs hatch.

With bristlenose plecos, its hard to state a specific growth rate. At times, they will remain between 3-4 inches for a long minute, and out of nowhere, they shot up to 6 inches.

Once the eggs hatch, newborns remain stuck and feeding on the egg sack for another 4 to 6 days before they become free-swimming.

After that period, they will start feeding on soft food for another month.

All this while, make sure you feed them well and ensure the water quality remains ideal for faster development.

The majority of your bristlenose fry will stay under an inch for up to 3 months, then from 4 months up to 6 months, they may develop to between 2 and 3 inches. It then takes up to 2 years for bristlenose pleco to reach the average maximum of 6 inches.

Breeding starts while the fry are between 6 months to a year old (sometimes 1.5 years), with an average body size of 3 to 5 inches.

Below is a quick (summerized) bristlenose pleco growth rate timeline:.

  • The life of a bristlenose start when the eggs, which take 4 to 10 days to hatch, finally break open and babies come out.
  • Fry remain attached to the egg sac for another 2 to 4 days feeding on the egg-matter, which is key to their survival during the initial hours of them being alive.
  • From this point on, most will become free swimming and will start feeding on algae, which you can supplement them with mashed vegetables such as peas.
  • Your bristlenose babies will remain under an inch for the rest of the month, only picking up in the 2 and 3 months, then grow up to 4 inches in six months.
  • Bristlenose plecos can be sexed and start breeding anywhere from 6 months to a year with an overall body size of between 4 and 5 inches
  • You can expect your bristlenose pleco to reach the full size of 6 inches within the second (2) year of them hatching.

What Size Tank Do Bristlenose Plecos Need

Given that they grow pretty small compared to other bottom-feeders, bristlenose plecos will live in a tank anywhere from 30 gallons and more. Some hobbyist even keep them in 20-gallon aquariums, but I do not recommend you do that.

Please note a bristlenose pleco cannot fit in a 10 gallons tank whichever way you look at it; not even one individual.

If you want a smaller bottom-feeder that will fit in a tiny tank (less than 30 gallons), consider getting dwarf suckers (Otocinclus) instead.

Also keep in mind that Siamese algae eaters are better algae-consumers than bristlenose plecos, so for bigger tanks with algae overgrowth, consider them as an alternative.

To best maintain your bristlenose plecos, provide them with a lot of caves and plenty of plants that provide hiding spots much like in their natural habitat.

Driftwood is also a good idea, and rocks will be appreciated too.

You can have more than one bristlenose pleco in your fish tank, as long as it is big enough for two or more, but try and avoid pairing two males as they tend to get aggressive towards each other.

When keeping more than one, I would probably go for a male and female pair in a 55 gallon, together with small fishes which have a small bio-load like tetras, rasboras, and white clouds.

Even so, look out for aggression from nippers like neon tetras as this might stress your plecos.

In bigger tanks like 75 gallons, a pair of bristlenose plecos can even live with dwarf cichlids from South America like german blue rams or even larger species like angelfish because they prefer similar water conditions.

I’ve even tried keeping bristlenose pleco with kribensis cichlids and I didn’t have much to complain about, so its another pairing you can try.

That’s all for this article, see you on the next one, and have fun with your bristlenose.

Eddie Waithaka

Resident Content Creator and Marketer at AquariaWise who talks about aquariums and fish and aquascapes a lot.

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