Twig Catfish (Farlowella acus) 101: Best Detailed Care Guide (2023)

By: Martin McAdam
Updated: March 19, 2022

Twig Catfish (Farlowella acus) are a very interesting group that is rapidly gaining interest in the hobby. Their aggressive nature, unique behavior, and imposing size make for an amazing showpiece species.

However, catching one of these elusive 'cats can be extremely difficult, especially given their nocturnal habits (it's not uncommon to do over fifty dives without seeing one).

Hopefully, this article will give you some insight into catching, keeping, and breeding these amazing fish.

Facts And Characteristics Of Twig Catfish

Given below are a few facts and characteristics of Twig Catfish

How Do Twig Catfish Look Like?

They have a very long fin base, which gives them the 'neon tetra' appearance. The dorsal and adipose fins are usually black with white tips, although they can appear more grey depending on mood/substrate color.

Twig Catfish

They are normally a few shades lighter below, which may appear as a white belly. The caudal fin is unique in that it has an elongated lobe (very similar to a blunted swordtail).

As they age, the head becomes extremely flattened and blade-like. They also have a prominent barbel on their chin.

The male differs from females in that they develop a very pronounced ventral keel and long, pointed genital papilla. Their second dorsal spine is greatly elongated and thickened in males, which is probably the easiest way to sex them.

Twig Catfish come in an amazing array of colors and patterns, from the standard black and white to red and white, yellow and brown (even a bright blue!). Just like any other color morph, it's impossible to predict what any individual fish may look like.

Temperament Of Twig Catfish

Their behavior is somewhat unpredictable, but they can generally be described as either aggressive or shy/passive.

Twig Catfish

The only way to figure out their mood for any particular day is to observe them and get a feel for how they behave (don't expect rapid changes in behavior, though).

They tend to become much more active at night when the lights are out. They are very shy when first introduced into the aquarium, laying on the bottom at night until they feel comfortable enough to venture about during the daytime hours.

Average Lifespan And Growth Of Twig Catfish

There isn't a concrete answer to this question. There are reports of people keeping them over ten years, but most specimens don't make it past three or four years (although this is not uncommon due to the finicky nature of the fish).

Twig Catfish

Twig Catfish can grow up to 6-8 inches, but it takes several years for them to reach this size. They weigh in at about a pound when they are fully grown.

The male twig catfish is much more elongated and thin than the female.

Habitat Of Twig Catfish

Twig Catfish are found throughout South America, specifically in the Amazon Basin. They are most prolific at the Negro River ("Negro" meaning "Black," so named due to its dark water) and Santarem but can be found downstream as far as Peru.

Twig Catfish

They prefer thickly vegetated areas with murky waters, like the Twig Catfish's native habitat. They like to root around in the substrate, so I would advise not using fine gravel (although they can be kept with coarse sand or small pebbles).

Also, these fish are very sensitive to sudden changes in water conditions and pH.

Breeding Of Twig Catfish

Yes, they can be bred, but it's very difficult. First off, you will need a breeding pair. Keep in mind that the young stay with the parents for several weeks after birth, so if you plan on spawning them in an aquarium- DON'T! Once spawned in the tank, predation of eggs/fry is likely to occur.

Twig Catfish

They are also very difficult to sex, so the only way to know you have a breeding pair is if they spawn in the tank. If you plan on raising them, I would suggest providing your breeding stock (after all, it's much easier than catching twig catfish).

If you do manage to catch some adults (and I mean a LOT), I would suggest a minimum of four adults to one hundred gallons. They are most prolific when fed live foods but can be weaned onto frozen products with relative ease.

They have been known to breed in aquariums as small as ten gallons, so it's just a matter of getting lucky and catching some adults (and having the room for them).

The breeding process starts with the male shaking/grinding its chin against a surface or other fish. The female will then swim between his pelvic fins, where he will fertilize her eggs as she expels them.

It is very difficult to tell if you have a successful spawn until around 30-40 days later when fry starts hatching (although there are reports of it taking up to 80 days).

The fry is very small (less than 3mm) and microscopically thin (so you can only see them with the aid of a microscope), so it is wise to remove the parents once eggs/fry start hatching.

Stories are floating around of people feeding microworms, infusoria, and even baby brine shrimp, but the most successful option I've seen is micro worms and finely crushed flake food. The fry grows very slowly, so you will need to be patient.

Twig Catfish should be kept in medium-sized groups once they are old enough to leave their parents (which can take a couple of months).

Twig Catfish Care Guide

Twig Catfish are one of the most popular freshwater catfish that are kept in aquariums; there are a few things to be kept in mind while taking care of the Twig catfish. They are as follows:

Tank Requirements

They need an acrylic fish tank with a capacity of at least 70 gallons with a fine or coarse substrate and some plants. The tank must be covered, as they are known jumpers.

Twig Catfish

They should also have some thickly vegetated areas filled with decaying leaf litter (so they can root around in the substrate).

They need to be kept in groups of ten or more, but make sure that they are introduced into the tank at the same time.

Their tank should have tough enough plants not to uproot (for example, Anubias or Java ferns) and floating plants that give the tank a thick, overgrown appearance.

Twig catfish should not be kept with other bottom-dwelling fish (like corydoras or plecos), as they may be outcompeted for food.

With hundreds of species to choose from, the beginner aquarist is often overwhelmed by the sheer number and variety of fish available.

As aquariums become more popular, manufacturers have responded with an amazing selection of equipment and accessories that help simplify both the selection process and maintenance work.

For example, the equipment used to maintain a basic freshwater aquarium can be divided into four categories:

  • Filters
  • Heaters and Thermometers
  • Lights

This breakdown should help simplify things for beginners by showing them which elements of their new system are most important while also making it clear that there are other options available.

The missing elements could easily be added after the tank is set up, or perhaps even later if the aquarist feels that they are necessary.

Another key point to remember is that there are very few absolutes when it comes to aquarium equipment selection.

While certain filters are better than others for most applications, there are always exceptions to every rule. For example, while external filters were once thought to be less efficient than internal models, that is no longer the case.

The key to choosing equipment and accessories for your new system is to simply focus on what you want and need from it. Only after this is determined should you start worrying about brand names or specific models.

After all, aquarium equipment manufacturers don't get to where they are by making poor-quality products.

Water Parameter And Temperature

They prefer water with a pH between 6 and 7 and a temperature between 74°F and 82°F. Twig Catfish are found in the backwaters of South America, which have a dark color caused by humic acids and tannins from decaying vegetation.

The TDS (total dissolved solids) is approximately 1000-1600ppm, with a pH around 5 to 7. When kept in aquariums, they prefer a pH of 6-7 and a TDS of ~500ppm. They need to be kept in dimly lit aquariums (with floating plants if kept with other bottom-dwelling fish).

Feeding Of Twig Catfish

Twig Catfish will eat just about anything, but I would recommend sinking catfish pellets, shrimp pellets, flake food, and micro worms for adults (with the occasional treats of bloodworms or brine shrimp). Again, I would like to stress that microforms are not suitable as a staple diet.

Twig Catfish

In the wild, Twig Catfish live on crustaceans and insect larvae diet. They are best kept in groups, and the coarse substrate is not advisable due to their rooting tendencies.

Also, they may uproot plants in the aquarium, so I would advise using hardy or heavy root feeders if you wish to keep these fish with plants.

They can be fed sinking catfish pellets, shrimp pellets, flake food, and micro worms in captivity. They should be fed at least once a day.


Twig Catfish are rooters, so they need to be provided with lots of time to root around in the substrate. They are known for uprooting plants, so I would advise using hardy or heavy root feeders if you wish to keep them with plants.

For example, I have mine with a bunch of Java Ferns, and they aren't uprooting them. When choosing a substrate, I would recommend using fine gravel.

They also appreciate large amounts of decaying leaf litter (such as oak leaves), which they will root through in search of food.

Tankmates Of Twig Catfish

These catfish are very peaceful and should be kept with other non-aggressive fish. They can be kept in groups of ten or more, but a tank of at least 100 gallons is a minimum.

Twig Catfish

They should be kept with larger fish that aren't known fin nippers. They can be kept with many different species, including Oscars, Severums, Jack Dempseys, Arawanas, Pimelodids, Hoplias ("Tiger Fish"), Red-tailed Catfish, Tinfoil Barbs, or larger Tetras. They can also be kept with Red Empress Cichlid (a large tank is needed).

Twig catfish should be kept in medium-sized groups (no less than three) once they are old enough to leave their parents (which can take several months).

Keep in mind that these fish get very large, so it's best to have a large tank with lots of hiding places. By nature, they are shoaling fish, so they should be kept together in a group of at least three.

Common Possible Diseases And Their Cures

Given below are listed a few common diseases and their cures of Twig Catfish.

1. Fungus

Fungal infections are generally caused by poor water conditions, which may result from overcrowding the tank or keeping live plants potted in gravel.

The solution is to not overstock the aquarium and keep only disease-resistant plants that are planted directly into the substrate (no pots).

2. Ich

Ich is an extremely contagious parasite that can be fatal if not treated immediately. The most common cause of infection is through the introduction of new fish before the existing population's immune system has had a chance to adjust to its new surroundings.

For this reason, it is always recommended to quarantine any newly purchased fish for at least two weeks before adding them to your aquarium.

3. Dropsy

Dropsy is a disease of the internal organs that causes the scales of infected fish to protrude from their body in a pinecone-like fashion.

The most common cause is poor diet, but it can also be caused by bacterial infection or damage to the kidneys and liver.

Dropsy occurs when the kidneys and liver become infected with a pathogenic bacterial species such as Aeromonas hydrophila, which can be present in poorly sanitized aquarium equipment.

Always keep your tank clean and practice proper biosecurity when introducing new fish to prevent this disease.

5. Holes in the head

Holes in the head disease (also known as "head and lateral line erosion") is a bacterial infection involving damage to the sensory organs surrounding the lateral line, allowing fish to detect motion in their surroundings.

For this reason, it is also sometimes referred to as "blindness." HITH occurs when bacteria such as Aeromonas hydrophila enter the sensory organs and begin to invade living tissue.

HITH is very difficult to treat once it progresses past the early stages, and medications such as Metronidazole become less effective. The best way to prevent this disease is through proper water parameters (low nitrates, high oxygen levels) and biosecurity.

6. Discus Euthanasia

Discus euthanasia is a disease that results from the stress of transport and relocation to a new environment, such as when purchasing them from a pet store.

The solution is to limit the number of times you purchase your fish and never release any aquarium fish into the wild.

7. Pop-eye

Pop-eye is a common disease that results from damage to the eye or poor water quality. The solution is to provide your fish with good water conditions and check the eyes for protruding retinas before purchasing it.

8. Mouth rot

Mouth rot is an infection of the mouth and gums caused by a bacterial species such as Flexobacterium.

Mouth rot starts by destroying the gills and quickly spreads to the rest of the body via the bloodstream. The solution is to ensure good water parameters (i.e., low nitrates) and provide frequent partial water changes.

9. Bloat

Flatulence in fish is caused by gas building up due to rotting food or poor water quality. The solution is to provide your fish with a well-balanced diet and keep the tank clean.


The best way to prevent disease is through proper water parameters (low nitrates, high oxygen levels) and biosecurity.

If you believe your fish has contracted an illness, the first thing you should do is perform a partial water change.

After removing about 20-25% of the tank's water, add treated tap water that contains dechlorinator to neutralize chlorine and chloramine in the new water.

Use an air pump to circulate the water inside the bucket to speed up the process. Next, feed your fish a nutritious diet, including vitamin C supplements to help boost its immune system.

Also, quarantine new fish for at least four weeks before introducing them to your main tank.

Are They Dangerous?

Twig Catfish are not aggressive towards other fish but may attack each other if overcrowded. They are very peaceful and make excellent inhabitants of the community aquarium.


It is beautiful fish that is fun to watch and easy to care for. Just be sure to research your other tank inhabitants before making a purchase.

These fish are sure to be a hit with everyone in the family. So why not give them a shot? You might be surprised at how much you enjoy having these fish in your tank.

Thanks for reading, and we hope this article was helpful.

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