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Fish, Shrimp & Corals


August 30, 2021 | By Tom Sarac

The bushy or bristlenose catfish is one of the most popular of the suckermouth catfish. A member of the Loricariidae family, the largest family of catfish on the planet, the Ancistrus genus is likely the best known. The genus consists of many species – at the time of writing, 76 are recognized – such as A. cirrhosus, A. pirareta, A. triradiatus, and others.

These highly useful suckermouths are compact in size, averaging around 3-4” / 7-10 cm in length. They are very interesting to observe as they move about and clean the surfaces in your aquarium, although it can sometimes be a challenge to find them as they spend a considerable amount of time in dark crevices or pinned against driftwood pieces. Unlike much of the rest of the Loricariidae group, 3 to 4 Ancistrus can easily be kept in a 20 US Gal / 80 L aquarium. Be aware that only one male should be kept in a tank of this size (males have more and longer tentacles on their heads than females). Due to their peaceful nature, Ancistrus can be kept with most community fish.

How are they useful? Ancistrus will constantly scour the glass, substrate and décor of their aquarium, effectively cleaning most surfaces and removing algae, even before it becomes visible. Note that this behavior can cause some compatibility issues with live plants: if live plants are present in an Ancistrus aquarium, make sure to feed the fish well, and be prepared to accept the loss of some broadleaved plants. For example, keeping Ancistrus with various species of Echinodorus usually results in the loss and destruction of at least some of the plants. Fast-growing, bunch type plants with small, narrow leaves are usually left untouched, but that is not guaranteed.

Originating from South America, Ancistrus are common in tributaries of the Amazon River, with different species being found in Argentina, Colombia, Brazil, Venezuela, etc. Ancistrus are found in slow to medium flow rivers and streams, often inhabiting sunken trees and branches. In faster-moving, clear water streams, they are often found in between boulders and rocks, effectively using these surfaces for their habitat and for feeding.


Taking care of Ancistrus is relatively straightforward. Like all tropical fish, regular water changes are key: changing at least 20% of the water once a week is recommended. Water chemistry is not as crucial as in some other cases: while many Ancistrus originate from softer, acidic water, they acclimate well to higher pH and hardness values, particularly if the fish are captive-bred (most Ancistrus available at fish stores are bred in captivity). Despite this, it’s always best to determine the conditions the fish are being kept in when purchasing any type of fish at your local retailer, and to gradually acclimate the fish to the conditions of your aquarium. When dealing with wild-caught fish, it is important to ensure they are first introduced to very similar water conditions as found in their natural environment. Later, a slow acclimation to slightly different pH and hardness levels can take place, if required.

When catching your Ancistrus, take note that this genus, like most suckermouth catfish, have sharp, stiff pectoral and dorsal fin bones, along with various hooks on their head and mouth area. This means they are prone to seriously tangling and hurting themselves in a typical aquarium net. To safely catch them, use a plastic container instead! Shift your aquarium décor or completely remove it, and then gently guide the fish into the container. If you have to remove your décor, check it carefully before doing so – Ancistrus will cling to it, and you may inadvertently remove the fish from the aquarium along with the décor.

Aquarium setup

When setting up an aquarium that will contain Ancistrus, you should choose either sand or fine, smooth aquarium gravel that is 1-3 mm in diameter. Since the fish naturally eat at the bottom of the aquarium, both sharp-edged and larger gravels are to be avoided: the former, as it can over time hurt the fish, and the latter, as food can become trapped and inaccessible to fish within coarser substrates, eventually decomposing. Smooth pebbles, stones, and driftwood should be incorporated into the aquarium as well. Over time, the wood will slowly be consumed by the fish, as they will grind away at the surface and keep it spotless. Take note that driftwood is a mandatory inclusion in an Ancistrus aquarium!

As for plants, we recommend avoiding any broadleaved plants like Echinodorus species. Ancistrus have a tendency of rasping these types of leaves until they are seriously damaged, potentially killing the plant. Fast-growing bunch plants with small leaves can be included in the aquarium as they are more often ignored by the fish, but make sure to feed plenty of vegetable-based tablet foods and slices of cucumber and zucchini on occasion to help keep the plants safe.


Ancistrus are easy to feed: they will accept many types of flake, pellet, tablet and frozen foods on the bottom of your aquarium. Remember, a varied diet is always best! A typical diet should consist of a quality sinking vegetable-based pellet food, a bottom feeder tablet, some fresh greens such as romaine lettuce or a slice of zucchini at least once a week, and some frozen food (vegetable mixes, brine shrimp, bloodworms, mussel, etc.) a few times a week.

Keeping and caring for Ancistrus is highly rewarding! They’re full-time housekeepers, they don’t compete with most other fish for swimming space, they feed at night from the bottom of the tank, and they’re great community fish. Remember, however, they aren’t “cleaner” fish – they require care and attention, like every other fish species.

If you’re looking for an interesting, useful addition to your aquarium, try an Ancistrus – you won’t be disappointed!


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