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Chaetostoma cf. thomsoni
Striped Bulldog Pleco, Rubber/Rubbernose/Rubberlip Pleco (L187b)

 Age of Aquariums > Freshwater Fish > Bulldog Pleco - Chaetostoma cf. thomsoni

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Chaetostoma_thomsoni_2.jpg (16kb)
Photo Credit: Ingrid

Name: Chaetostoma cf. thomsoni
Size TankpHTemp
Origin: Magdalena Basin (Colombia)
10 cm 60 L 7.0 23°C


Chaetostoma is a genus of freshwater loricariid catfish, of the family Loricariidae, the armored suckermouth catfishes. A genus with many undescribed species, mixed groups or individual members may be labeled for sale as “Chaetostoma spp.”, or “Chaetostoma sp.” meaning, “this is a species of Chaetostoma, but we don’t know which.” The fish illustrated in this profile is usually identified as Chaetostoma thomsoni, or Chaetostoma cf. thomsoni, indicating its formal identification as “thomsoni” is under review. At this time, material has come forward to suggest that the specific name of thomsoni may not apply to this species at all! Also known as L187b, some common names for C. cf. thomsoni are bulldog pleco, rubbernose pleco, green rubber pleco, rubberlip pleco, and variations of those terms. Sometimes the word "striped" is added to the common name.

Species of Chaetostoma are collected from many freshwater mountain streams and tributaries of the Rio Magdalena river system in Colombia, South America, on the western slopes of the Andes Mountains. The species that finds its way into the hobby most frequently is very possibly collected from as far away as the fast-flowing mountain stream beds on the eastern slopes of the Andes Mountains, in the area known as the Llanos drainages.

Despite its small adult size, this catfish has the widest mouth of any of the loricariids! Juveniles offered for sale are quite small, but vigorous. The adults are impressive, with black dots on their faces and a black line articulating each overlapping bony plate of armor on the body. At night, in my community tank of white sand, the little bulldog pleco adopts camouflage, and will turn almost white to match the sand.

Chaetostoma cf. thomsoni appreciates clean, highly oxygenated water, which can usually be provided with regular water changes and a swift return flow from your filter. Some hobbyists add a powerhead at one end of the tank, but too many attachments can heat up the water. Remember to keep the water in the cooler tropical temperature range for this species. I provide an open topped set-up, and HOB filter with a splashy return, which helps to keep things cool.

My tap water is very soft, and white marine sand substrate, as mentioned above, is my choice for adding a few degrees of hardness and keeping the pH near neutral. If you already have slightly hard water, and your pH stays in the suggested range of 6.8 to 7.8, look into fine substrates that won’t elevate the hardness further. The cooler water temperature is more important than a specific hardness or pH.

The bulldog pleco spends a lot of time exploring the glass for food, but ultimately it is a bottom dweller, too, and appreciates a very fine substrate to scoot around on. I use lots of smooth rocks over the sand, in a well-planted tank, and I often see mine bustling through the sand or on the rocks, resting. Even though this species stays small, I would recommend a tank volume of no less than 60 liters, and tank dimensions of no shorter than 60 cm long. When their simple requirements are met, Chaetostoma cf. thomsoni are remarkably easy to keep, despite their exotic appearance.

This small suckermouth species can be territorial with its own kind and other small pleco-type catfish, thus the name “bulldog.” It is not shy about approaching food, and will scatter its tankmates with bold movements. It is peaceful, but not timid. I keep only one C. cf. thomsoni per tank, but in larger tanks you could keep more. Provide each fish with a choice of smooth rocks, and arrange discrete areas to satisfy their territorial needs.

This fish is a good glass cleaner, and loves algae of the type that forms a film on the glass and other tank surfaces. It will eat most other typical aquarium foods, even flake, but do not make this their main diet. Fresh veggies, such as zucchini, seem to be appreciated. Frozen bloodworms, and other meaty foods, should be offered about once a week, as their protein requirements need to be met. They are true omnivores, and quick to identify delicious food in the tank!

I learned a lot from my first Chaetostoma. Within minutes of adding one to a 75 liter South American community tank, the tank dynamics changed. The Chaetostoma rousted the Otocinclus from their room behind a piece of slate - where they had been living for the last 2 1/2 years - and moved himself in. There was no question about who was the boss, and the Otos went off to set up house in a different part of the tank. Peace reigned, and there were no problems between the two species. They even shared a zucchini slice, with the Chaetostoma on top and the Otocinclus circling the rim. Every time the Otos came around, the Chaetostoma would lift his tail to let them pass! Territorial but peaceful; assertive but reasonable - that describes Chaetostoma cf. thomsoni, the bulldog pleco!


I use to have one of these guys. Mine was named Ryan and I had him for about 3 years. I bought a new fish for the tank one day, but it was sick, and Ryan died. The name bulldog suits well. I found Ryan to be very bullheaded, and never wanted to leave his barrel. He didn't really like the other fish, or care for them. He was also a very quick swimmer! I miss my fish, but can't seem to find one anywhere in this town! I highly recommend this fish, but they stay small, so don't put him in a big tank, you'll never see him!

Contributed by Tina Borris

The bulldog pleco is one of the most amazing and interesting plecos that a hobbyist can own. Mine started out as a small 3 cm fish and along a year he has maxed out at over 8 cm. When I first introduced him to my tank he was terrified of all my other fish and extremely scared of me. He would rush out from behind his hiding place to eat for a few seconds and then would dart back to his rocks whenever a small fish approached him. After a while he began to show his true colors when a tasty morsel of food landed near my 13 cm common pleco. At first I wasn’t sure what was happening but, my 3 cm bulldog pleco was actually viciously attacking my significantly larger common pleco!

It wasn’t long before my bulldog pleco had asserted himself as the ruler of all other plecos. A few months later he started showing my geophagus cichlid and corydoras catfishes that he was boss of the tank whenever there was food around. Being nocturnal, he usually rests most of the day unless he sees another pleco but, when there is food around, he makes sure he gets his share and that no other fish can steal his morsels of food. Luckily his attacks never leave any other fish injured or overly stressed (especially towards his usually victims the cory cats, who are usually unphased by the attacks).

Mine changes color constantly and can range from sulfur yellow to a light green color. My pleco also has a habit of digging and I have to protect my planted aquarium by placing rocks around all the plants because it will dig and unbury their roots, leaving them exposed. He currently has dug himself a cave under a large peace of slate and it is amazing to watch him venture from under his rock and scatter the little persistent corys in his pursuit of food. This is definitely a fish with a spunky and interesting attitude that will do an impeccable job at cleaning algae while showing a personality that you will never find in a common pleco.

Contributed by Ronald

My Rubbernose started off shy, but once I put a big rock in the tank, he warmed right up (they live in a habitat of rocks and they LOVE them). He defends his rock like it were his baby, and neither of the Bristlenose Plecos are so much as allowed to sniff it. When I initially put the rock in there, I had grown algae on it and everybody wanted a part of it. The Rubbernose sent them all packin', but the BNs were persistent. Plus, I swear they teamed up. One would settle down on the rock, the Rubbernose would bolt after it and chase it off. He'd come back to his rock to find the other BN had claimed it, and he'd send that one running. He'd come back, and the first BN had come back to the tank. They ran him ragged, but they've settled down now and don't care for the rock anymore. The driftwood is good enough for them, but one set of driftwood is next to the rock, and naturally the Rubbernose has claimed that as his own, too (I think he loves the fact that a certain spot, a gap between the two driftwood pieces, conceals him and yet gives him a great view of anything coming towards him).

If your Rubbernose is a shy sort who spooks easily (like mine was when I first got him), find a rock for him. But not any old rock you find that's in an area where it could have been contaminated with chemicals and car exhaust! My guy is much calmer and self-assured now that he has his rock, and I find it so amusing to watch him protect that rock from the other plecos, and even the Loaches.

Contributed by Ingrid

This is a beautiful fish with great coloration for a pleco. I don't have any visible algae, so I supplement his diet with algae wafers. I haven't seen him eat them yet, the only ones who have been seen eating the wafers are my 5 albino corys. But according to my other experiences with plecos, I know that he will be a good cleaner of algae when the time comes. One of the cons with this little guy is that he is extremely shy. That might even be an understatement. He has only ventured out from under his tree trunk 3 times in the 2 months I've had him, as far as I know. And whenever I come to the tank, he seems to be watching, and he freaks out and hides. But he and my leopard bushfish share the tree trunk, with him on the ground under the roots, and the bushfish in the trunk. I think as soon as the leopard bushfish gets big enough to take him on, the pleco will be forced to move out and find another spot. Then I might get to see some action.

Contributed by Spencer Henry

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