Zbrojnik (Pleco / Suckermouth Catfish) – Ancistrus sp.

Suckermouth catfish from the Ancistrus group, commonly called Pleco or bushynose catfish, are among the most useful and attractive fish in freshwater aquariums. Peaceful behavior, interesting appearance and their talent for eating algae make them a favorite of both beginners and advanced aquarists. In this article you will learn how to keep them healthy, how to choose tank mates, what to feed them and how to arrange the aquarium so that they show their natural behavior. At MB Store you will also find a full range of aquariums and aquarium equipment perfectly suited to keeping Ancistrus catfish.

Characteristics and natural behavior of Ancistrus

Ancistrus catfish come from South America, where they inhabit streams and slow-flowing rivers rich in roots, branches and stones. In contrast to many large plecos, most Ancistrus stay relatively small, usually around 8–13 cm, which makes them ideal for home community aquariums. Their body is flattened towards the underside, with a wide head and a large suckermouth that allows them to cling to surfaces and rasp off algae and biofilm.

A characteristic feature of adult males is a crown of “bristles” on the head, which are much weaker or absent in females. This makes Ancistrus one of the easier catfish to sex. They are mainly nocturnal. During the day, they prefer to hide in caves, under roots and in dense plantings. At dusk they become more active, browsing glass panes, stones and decorations in search of food. Despite the common opinion that they eat “only algae”, in reality they are omnivores with a strong preference for plant food.

Ancistrus are peaceful, but males can become territorial towards each other, especially when there are not enough hiding places. They do not attack other species, although they may push small fish away from their favorite driftwood or cave. Their strong mouth helps them hold onto surfaces even in stronger currents, so a properly set filter outlet is not a problem for them, but a source of natural stimulation.

Aquarium setup and water parameters

Although Ancistrus are considered resistant and forgiving of mistakes, they show their full potential only in a properly arranged aquarium. For a single specimen, an aquarium of at least 60 liters is recommended, but for a small group it is better to choose 80–100 liters or more. MB Store offers aquariums in various sizes and shapes, which will allow you to match the tank both to the needs of the fish and to the place at home or in the office.

The optimal substrate is fine gravel or sand, in which Ancistrus can safely search for food residues without the risk of damaging the mouth. A key role is played by driftwood and roots – not only as hiding places, but also as a natural source of fiber. Ancistrus rasp off the surface of the wood, which supports their digestion. You can supplement the decor with stones and ceramic caves that will serve as shelters and potential breeding places.

As for water parameters, Ancistrus prefer temperatures in the range of 23–27°C, pH 6.5–7.5 and moderate hardness. They adapt well to typical conditions in a community aquarium, provided that the water is clean and stable. Efficient filtration is necessary because, like other catfish, they produce a relatively large amount of waste. MB Store offers internal and external filters that will provide adequate circulation and mechanical as well as biological filtration.

Lighting does not have to be very intense. Moderate lighting, with darker corners and shaded areas, will encourage Ancistrus to be more active. Plants such as Anubias, Java fern or Cryptocoryne tolerate dim locations and look natural among roots and stones. Remember to ensure good oxygenation of the water – surface movement and properly selected filter power are usually sufficient, and in more heavily stocked tanks, an additional aerator can be useful.

Diet and proper feeding

The belief that Ancistrus live “on algae alone” often leads to malnutrition. Although they eagerly eat algae, this is only one element of their diet. In a well-maintained aquarium, algae may even be too little to cover their needs. The basis of feeding should be high-quality sinking tablets and wafers with a high content of plant ingredients, such as spirulina, vegetables and plant fibers.

Ancistrus value fresh vegetables: slices of zucchini, cucumber, blanched spinach or peas. Vegetables should be removed from the aquarium after a few hours so as not to degrade water quality. It is worth providing a varied diet by adding foods of animal origin in moderation: frozen bloodworms, daphnia or high-protein granules. Excessive protein may cause digestive problems, so it is better to use it as an addition than a base.

An important component of the diet is natural wood, from which Ancistrus rasp off small fragments. They do not eat it as a classic food, but fiber and lignin support the functioning of the digestive system. Therefore, even in an otherwise decorated aquarium, one or two suitable pieces of driftwood should be present. MB Store offers prepared, aquarium-safe driftwood that does not release excessive tannins and does not negatively affect water parameters.

Feeding is best done in the evening, when Ancistrus become more active. This way, fast fish from the upper zones of the aquarium will not eat all the food before the catfish can reach it. Sinking tablets placed near hiding places or under roots will quickly be found. Regular observation of body shape is important: a healthy Ancistrus should be full, but not swollen, and the abdomen should not be sunken.

Compatibility with other fish and community aquariums

Ancistrus are extremely valued in community aquariums because of their calm disposition and helpful nature in controlling algae. They do well with most peaceful fish species: tetras, barbs, gouramis, rasboras, livebearers and many others. They are not interested in fish fry as food, although accidental incidents may occur when they browse through the bottom for leftovers.

The main aspect to watch out for is aggressive or strongly territorial bottom fish, such as some cichlids or large predatory species. In such company, Ancistrus may be harassed or deprived of access to food. In the case of medium-sized cichlids, such as some Apistogramma, peaceful coexistence is possible provided that caves and hiding places are plentiful, and each species can occupy its own territory.

Keeping several males in one aquarium is possible, but requires more space and more hiding places. In too small a tank, males may fight for caves, especially during the breeding season. If you plan to keep a group, it is safer to choose one male and several females, or to provide an appropriately large aquarium with a complex arrangement of roots, stones and caves.

Ancistrus also adapt well to planted aquariums. They rarely damage healthy plants, although they may rasp soft or decaying leaves. Their constant browsing helps remove algae films from tough leaves of plants such as Anubias or Java fern. However, they will not replace good aquarium maintenance: regular water changes, proper lighting and fertilization are still necessary for aquascaping success.

Breeding Ancistrus in the home aquarium

Breeding Ancistrus is considered relatively easy and is often one of the first breeding projects for beginner aquarists. The key is to provide appropriate caves and calm conditions. The male chooses a cave, cleans it and encourages the female to lay eggs. Caves can be created from ceramic tubes, hollow stones or specially designed shelters, readily available in aquarium stores.

After the female lays eggs, the male takes over full care. He fans the eggs with his fins, providing them with oxygen and removing unfertilized or damaged ones. During this time, he may become more territorial, defending the area around the cave against other fish, including humans approaching the glass. After several days, small fry hatch, which initially feed on the yolk sac, and then begin to look for food on their own.

Feeding the fry requires finely crushed vegetable foods, spirulina powder or specialized food for juvenile catfish. Fresh vegetables cut into small pieces are also well accepted. Water changes should be regular but gentle, to avoid sudden changes in parameters. Good filtration is required, but strong current should not be directed directly at the cave with fry.

Breeding Ancistrus in a community aquarium is possible, but many fry may be eaten by other fish. If you want to raise a larger group of juveniles, it is worth transferring the cave with the guarding male to a separate breeding tank with the same water parameters. MB Store offers small tanks and aquarium accessories that make organizing such a breeding aquarium easier and safer.

Health, longevity and common problems

Ancistrus, with proper care, can live 5–10 years, and sometimes longer. Their resistance does not mean they are indestructible; poor conditions or malnutrition quickly lead to health problems. One of the first warning signs is a withdrawal into hiding and refusal of food. Changes in the structure of the fins, white patches or visible thinning of the body also indicate trouble.

The most common problems involve water quality. Elevated levels of nitrogen compounds (ammonia, nitrites, nitrates) weaken fish and promote the development of bacterial and fungal infections. Regular water changes, efficient filtration and moderate stocking are the basis of prevention. When selecting filters and other equipment, it is worth using proven products – MB Store offers sets that facilitate matching the filter to the size and type of aquarium.

Another recurring issue is damage to the fins and skin, often caused by inappropriate decorations with sharp edges or conflicts with other fish. When arranging the aquarium, choose natural or specially prepared decorations without sharp elements. Quarantine for new fish and plants reduces the risk of introducing parasites or pathogens, which is particularly important in tanks with long-lived and valued species like Ancistrus.

Digestive problems usually result from excessive protein in the diet or the lack of plant ingredients and wood. A well-balanced menu, rich in vegetables and plant-based foods, effectively prevents bloating and constipation. Observing excrement, body shape and activity makes it easier to react in time and, if necessary, consult with an experienced aquarist or veterinarian familiar with ornamental fish.

Equipment and accessories useful for keeping Ancistrus

Although Ancistrus do not have extremely high requirements, the right aquarium equipment significantly facilitates their proper care. A reliable heater with a thermostat ensures stable temperature, which is crucial for immunity and metabolism. A filter with appropriate capacity keeps the water clean, oxygenated and free of suspended solids accumulating on the bottom.

Lighting should be adapted to plants and the comfort of the fish. If Ancistrus are to be kept with demanding plants, modern LED lighting with adjustable intensity and spectrum will be useful. MB Store provides a wide selection of such lamps, allowing you to match the solution both to a decorative aquarium and a functional tank focused on breeding or maintenance.

Additional accessories, such as test kits for measuring pH, hardness and nitrogen compounds, allow for ongoing control of water parameters. Thermometers, timers for lighting, nets, siphons and tools for aquarium maintenance complete the set of essentials for every aquarist. By using comprehensive offers such as those available at MB Store, you can build an aquarium stable enough for Ancistrus to thrive, grow and, if desired, successfully reproduce.

Why Ancistrus are a good choice for beginners and advanced aquarists

Ancistrus combine several features that make them one of the most recommended fish species. They are hardy, tolerant of minor parameter fluctuations and rarely aggressive. At the same time, they contribute to the cleanliness of the aquarium by eating algae and food leftovers from the bottom and decorations. Their interesting appearance, especially in the case of males with “bristles”, adds originality to any arrangement.

For beginners, Ancistrus are a forgiving species that teach the basics of aquarium care: proper feeding, maintaining water quality and observing fish behavior. For advanced aquarists, they offer the opportunity for fascinating breeding projects, color morph selection and experimenting with different arrangements and biotope setups. They also harmonize well with both classic community aquariums and more sophisticated plant and aquascaping compositions.

By choosing Ancistrus and equipping the tank with properly selected equipment, you create a stable, attractive ecosystem in which fish can show their natural behavior. MB Store supports aquarists at every stage – from choosing an aquarium and filtration, through lighting and decorations, to specialized foods and accessories. Thanks to this, keeping Ancistrus becomes not only possible, but also comfortable and satisfying in the long run.

Practical tips for everyday care

Daily care of Ancistrus is not complicated, but regular routines are crucial. Feeding at fixed times, preferably in the evening, helps control the amount of food introduced and observe appetite. Weekly partial water changes, usually 20–30%, keep parameters stable and remove accumulated nitrates. Pre-cleaning the substrate with a siphon prevents organic debris from rotting.

Glass cleaning should be done carefully, leaving some areas with a thin algae film as a natural food source. Decorations and driftwood are better cleaned occasionally so as not to completely remove the biofilm and microorganisms that Ancistrus browse. When servicing the filter, avoid washing all filter media at once; rinse only part of them in aquarium water to preserve beneficial bacteria.

Observation of behavior is an invaluable diagnostic tool. Ancistrus should regularly appear in open areas, especially at dusk, and show interest in food. Extended hiding, accelerated breathing, clamped fins or visible lesions on the body are signals to react. Early intervention usually allows for quick correction of mistakes, such as overloaded filtration, inappropriate diet or insufficient ventilation.

Introducing new fish or changing decor is best done gradually. Sudden rearrangement can disrupt the territorial arrangement, especially among males. When adding new roots or stones, check that they are safe for aquarium use and properly prepared. Using proven decorations and equipment, such as those available in MB Store, reduces the risk of unwanted substances entering the water and helps maintain a stable environment for your Ancistrus and other inhabitants.

FAQ

How big do Ancistrus catfish get and what tank size do they need?
Most common Ancistrus varieties reach about 8–13 cm in length, which makes them suitable even for medium-sized home aquariums. For a single specimen, 60 liters is the recommended minimum, but a larger tank, 80–100 liters or more, is better, especially if you plan to keep a pair or small group. More space allows natural behavior and reduces territorial conflicts.

Do Ancistrus really clean the aquarium from algae?
Ancistrus effectively eat algae films from glass, stones and driftwood, helping to keep surfaces clean. However, they are not a complete remedy for algae problems, which are usually caused by excess light, nutrients and poor maintenance. They should be treated as support, not a substitute for water changes, filtration and balancing lighting and fertilization in a planted tank.

What is the best food for Ancistrus catfish?
The ideal diet is based on sinking plant-based tablets and wafers, rich in spirulina and vegetables, supplemented with fresh vegetables such as zucchini or cucumber. From time to time you can add small portions of food of animal origin, for example frozen bloodworms. It is important that protein is an addition, not the basis, and that driftwood is present in the aquarium as a natural source of fiber.

Can Ancistrus be kept with shrimp and small fish?
Ancistrus are generally safe for most community fish and larger shrimp. They are not active predators and do not hunt fry or adult shrimp, but may inadvertently eat very small individuals while browsing the bottom. Proper feeding and plenty of hiding places minimize this risk. With nano shrimp, it is better to ensure dense plants, mosses and shelters to increase their safety.

How to distinguish a male from a female Ancistrus?
In adult Ancistrus, males develop characteristic “bristles” or tentacles on the head and around the mouth, often forming a crown extending towards the center of the head. Females usually have few, short bristles or none at all, and their body shape is more rounded, especially when carrying eggs. Differences are best visible in mature fish; juveniles can be difficult to sex reliably.