Pleco Aquaponics – Living Filters.

What in the world is a "Pleco" ?
They are a breed of fish. The scientific name is Hypostomus plecostomus (known commonly as a sucker fish) They are freshwater fish and are native to tropical Central and South America.

Pleco fish in my Aquaponics system  Murray Hallam Practical Aquaponics

Pleco "sucker" fish. Three beautiful specimens.

They are capable of consuming large quantities of algae.  Plecos' also consume anything that is left on the floor of the fish tank such as uneaten fish food and solid material that may settle in the corners of the tank or around structures such as the submersible pump. They do a really good task of keeping the pump exterior clean.
These fish are a very useful addition to any Aquaponics system assisting in the processing of waste material from the principal fish colony that you keep in your system.

Recently we added one Pleco to our floating raft system fish tank. This particular fish tank is located in the greenhouse and is subject to getting sunlight all day every day.  It has become a standard maintenance practice to scrub the sides and bottom of the tank every couple of weeks in an attempt to keep the build up of algae under control. It is a neverending task and one that we fall behind on at times.

Pleco fish in with Jade perch. Murray Hallam Practical Aquaponics.

The Pleco shares the tank with some Jade Perch and keeps the tank really clean.

Placing the Pleco in the tank has had amazing results. The tank is now very clean both sides and bottom.

The Pleco gets on well with the Jade Perch in the tank. I guess we will find out over time if it remains that way. As the Pleco gets some real size the "balance-of-power" may shift.    It would appear that this is a very good way to keep the tanks clean in a home Aquaponics system.   We have obtained another 15 Plecos and have distributed them around our various systems and are enjoying seeing their work expand each day.  Every morning it can be clearly seen the progress made the night before as they work their way around the bottom and sides of their new home.

The most interesting will be the progress of 10 very juvenile fish in to the raft tank on our floating raft system.  They will grow fast over summer and should do well in their new surroundings.  Very fine solids drop out of the water as the water passes slowly through the raft tank depositing on the bottom in a layer about 6mm (1/4") deep.  This material accumulates to this depth over about a 6 month period.  The main filter system does not catch all the very fine material and this accumulates in the bottom of the rafts.

Pleco fish in Murray Hallam's Aquaponics system

The Pleco hides in the rear most corner during the day. Pleco do their best work at night. A living filter system !

I am confident that the Pleco fish will clean all this up as part of their "daily bread".   This will effectively process the very fine solids and keep the nutrients in the Aquaponics system to be taken up by the plants.  The only thing left behind by the Plecos is their own waste material.   This material will eventually move through the system and be trapped by the filter system.  The important thing is that the nutrients are retained in the system rather than being cleaned out and discarded.

I think of my Plecos'  as "Living Filters" for my Aquaponics system

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19 thoughts on “Pleco Aquaponics – Living Filters.

  1. Hi Peng, no they won’t.
    I have kept Ell-tailed catfish in all my tanks for the last couple of years. They do not do much of job compared to Plecos’
    As I can catch them, I am moving my Ell-Tailed catfish to tanks that I will not heat over winter. They handle the cold really well and are as tough as old boots…. Hard to kill but good to eat ….so I am told.

    • Hi David,
      I have not done that but I imagine there would be conflict between the red claw and the plant roots.

  2. So that’s what they are called…in my whole life I’ve never met anybody here who ever knows what those fish are called…we just mention them as “ikan DBKL”~the cleaner fish…but there have been claims that large Pleco fish would harm smaller fish/fingerlings, not sure if this is true, just a rumour I heard but it’ll be wise to find out….

    • Hi Arthoz,
      The information I have is that they are ok with other fish so long as the other fish are bigger than them. So far in my tanks (I have them in three different Aquaponics systems) I have had no trouble at all. The Pleco fish are doing a great job of keeping things clean.

  3. Another possible piece of the puzzle! What a fun addition – my mom has had a pleco in her hobby fish tanks for as long as I can remember to save her the trouble of cleaning the algae off the sides of the aquarium. I used to sneak in very slowly to the room with aquarium to try and catch a glimpse of the pleco at work against the glass, usually only getting a moment before the fish darted off to hide under its favorite sunken ship ornament.
    According to Wikipedia they also appreciate snacks of cucumbers and lettuce – wonder what other aquaponic produce scraps they might like?

  4. I have been thinking of adding plecos to the troughs of my DWC, but was reluctant because I was scared they would eat my roots. I have two in my Tropical Fishtank and I give them greens for a treat, and boy do they tear em up. I was wondering if you have had any problems with this? If not, I will be adding them to my system soon. I had other thoughts of adding Oto Catfish if the Plecos were a problem. I also want to add some Guppies and/or Mosquito Fish to keep down on the pest. Do you have any experience with this?? If so, Do you have any suggestions for me?

    • Hi Mason, Maybe you have a different strain of Pleco. Mine do not touch lettuce leaves and the like. Perhaps they are well satisfied with the amount of algae etc they are getting anyway not to be bothered with the roots of the plants. In a few more months I will be better informed on their habits. It takes time to observe these things fully.

  5. Hi, i have a Pleco in my tropical fishtank. He doesn’t hurt any other fish while they are moving. Once dead, they are eaten soon. He eats up everything except a long-leaved plant, i don’t know the name of it. I have baby guppies, they are cleaning his back and he doesn’t hurt them.

    • Hi Ditte, Pleco’s are most useful that is for sure. I have them in three different systems now and they are doing a great job of cleaning the fish tanks.

  6. hi we have plecos in with goldfish and with small fish even discus , they are algae eaters, when a fish dies in the tank they will suck all the slime off the dead fish and clean it up they will also eat frozen meat if it is on the bottom of the tank, Blanched lettuce, silver beet, continental and lebonese cuccumbers cut in stripps, broccoli, carrot and even pumpkin is consumed by these catfish. common plecos can reach 2 foot in the wild and around 18” in a tank there are smaller plecos like the chocolate pleco and some of the L number catfish, the bristle nose catfish is from the same family it was called hairy nosed pleco however everyone knows it as a bristle nose cat. we move two of our shop plecos from tank to tank just to clean the algae off the glass, they do a whole tank overnight best algae cleaners.

  7. Hello Mr. Murray,

    Thanks for this input. I am in the first stages of operating an Aquaponic system in the Philippines. I was actually getting tired of cleaning the grow tanks every other week. This suggestion seems to be the “hidden treasure” I was looking for.

    Incidentally, I am having some problems with mosquito larvae in my DWC grow beds. I was thinking of putting some small fish like a swordtail so they can eat the larvae. Any thoughts about their co-habitating with a pleco? Also any other fish suggestion that will eat mosquito larvae and not harm my roots would be useful.

    • Pleco will co habit with most fish I have found so sme small type of fish that will eat the mosquito would be good

  8. I used plecos in my sump tank, they cleaned it up well.
    We had plecos in the fish tank but they got about 1/2 the size of my cat fish and sucked a hole in the side of one of them. Not sure what “type” of pleco it was.

    • Hi Bob,
      They are pretty good that’s for sure. Unfortunately I only have a few left now and I can’t buy anymore. I have discovered they do not like cold water.