C001 Icana Corydoras

Quick summary

The Icana Corydoras (Brochis incolicana) is a rare and genuinely under-documented catfish originating from the upper Rio Negro basin in Brazil. It is best suited to experienced keepers who can provide soft, acidic water and who are comfortable maintaining a species with limited published care data. Because so little has been formally documented about its specific requirements and breeding, prospective owners should be prepared to rely partly on general Corydoras husbandry principles while remaining honest about the gaps in species-specific knowledge.

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Last researched and fact-checked: June 2025.

• Introduction
• Quick Stats
• Appearance
• Natural habitat
• Tank size and setup
• Water parameters
• Filtration and equipment
• Diet and feeding
• Behaviour and temperament
• Tank mates
• Breeding
• Common diseases and health
• Frequently asked questions
• Related guides

Introduction

The Icana Corydoras holds a special place in the history of aquarium catfish taxonomy. In 1993, DATZ (Die Aquarien und Terrarien Zeitschrift), the German aquarium magazine, assigned it the designation C001, making it the very first Corydoras to receive a C-number. This numbering system was created to catalogue the many undescribed or newly discovered Corydoras-type catfish entering the hobby, and C001 was where it all began. At the time, the species lacked a widely used common name, and the C-number system provided hobbyists and dealers with a practical shorthand for identification.

Scientifically, this fish was formally described as Corydoras incolicana, a name referencing its type locality on the Rio Icana in the upper Rio Negro basin, Amazonas, Brazil. For decades it sat within the enormous genus Corydoras. However, in 2024, a major taxonomic revision by Dias et al. reassigned it to the resurrected genus Brochis. This revision placed several species into Brochis based on phylogenetic analysis, and Brochis incolicana now reflects the current accepted classification. Despite this change, the species is still overwhelmingly sold under its former name, Corydoras incolicana, in the aquarium trade, and many hobbyists and retailers continue to use that name. Both names refer to the same fish.

It is important to be upfront about the limitations of the available information on this species. Brochis incolicana is rarely imported, infrequently kept compared to mainstream Corydoras species, and has very little species-specific published research beyond its taxonomic description and basic collection data. The IUCN lists it as Data Deficient, meaning there is not enough information to assess its conservation status with any confidence. Much of what follows in this guide draws on what is documented for the species directly, supplemented where necessary by general principles from closely related Corydoras and Brochis species. Where species-specific data is lacking, this guide says so plainly rather than presenting assumptions as established fact.

Some online retailers and importers list this species as originating from Peru or Colombia. These attributions conflict with the type locality and confirmed collection records, which place the species in the Rio Icana drainage of the upper Rio Negro basin in Amazonas, Brazil. This guide uses the Rio Icana, Brazil origin as the reliable one, consistent with FishBase, PlanetCatfish, and the original species description.

Appearance

Brochis incolicana is a modestly sized armoured catfish with the typical Corydoras body plan: a compact, laterally compressed body protected by two rows of bony scutes running along each flank. Like all callichthyid catfish, it has a flattened ventral surface suited to a bottom-dwelling lifestyle and a pair of short barbels around the mouth used for foraging in the substrate.

The base colouration tends towards a pale to light tan or cream body, overlaid with a pattern of dark spotting or blotching. The precise patterning can vary between individuals, and the overall impression is of a subtly marked, understated fish rather than a boldly patterned one. The fins are generally clear or lightly spotted. Detailed published descriptions of colour variation, sexual dimorphism, or ontogenetic colour changes in this species are sparse. In many Corydoras and Brochis species, females tend to be slightly larger and broader when viewed from above, particularly when gravid, and this is likely the case here, though documented confirmation for B. incolicana specifically is limited.

This is not a fish that leaps out visually in a mixed community tank in the way that some of the more dramatically patterned Corydoras species do. Its appeal lies more in its rarity, its historical significance as C001, and the satisfaction of keeping a genuinely uncommon species well. Hobbyists who have kept it often note its quiet charm rather than any flashy appearance.

Natural habitat

The type locality for Brochis incolicana is the Rio Icana, a major tributary of the upper Rio Negro in Amazonas state, Brazil. The Rio Negro system is one of the world’s great blackwater river systems, characterised by tea-coloured water stained dark by dissolved tannins and humic acids leaching from decaying vegetation in the surrounding forests. These waters are typically extremely soft, highly acidic, and low in dissolved minerals.

The Rio Icana itself flows through dense tropical forest. Water conditions in this system are generally very warm, with temperatures commonly in the mid to upper twenties Celsius, and pH values that can drop well below 5.0. General hardness is negligible, often barely measurable. The substrate in these habitats tends to be sand, fine gravel, or leaf litter over a clay or mud base, with abundant submerged wood and fallen leaves providing shelter and foraging surfaces.

Aquatic biodiversity in the upper Rio Negro basin is high, with numerous species of small characins, cichlids, and other catfish sharing the same waterways. However, the nutrient-poor, acidic conditions mean that overall productivity is relatively low compared to whitewater Amazonian rivers. Fish in these environments are adapted to conditions that many aquarium species would find inhospitable, which is an important consideration for anyone attempting to keep B. incolicana in captivity.

Detailed ecological studies focusing specifically on B. incolicana within this habitat are not available in the published literature. What is known about its microhabitat preferences, diet in the wild, breeding season, or population density comes largely from inference based on collection locality data and the broader ecology of the Rio Negro system.

Tank size and setup

A minimum tank volume of 75 litres (approximately 20 US gallons) is recommended for a small group of Brochis incolicana. As with all Corydoras-type catfish, these are social animals that should be kept in groups of at least six individuals. A larger group in a larger tank is always preferable, both for the fishes’ comfort and for the keeper’s ability to observe more natural behaviours. A tank of 100 litres or more would be a better starting point if space and budget allow.

The substrate is one of the most important elements of the setup. Corydoras and Brochis species spend the majority of their time on the bottom of the tank, foraging through the substrate with their sensitive barbels. Sharp or coarse gravel can damage these barbels over time, leading to erosion, infection, and reduced ability to feed. Fine, smooth sand is the ideal substrate choice. Play sand, pool filter sand, or purpose-sold aquarium sand all work well, provided the grain size is fine and the edges are not sharp.

Decor should aim to replicate, at least broadly, the conditions of a blackwater forest stream. Driftwood, particularly bogwood or Malaysian driftwood, serves multiple purposes: it provides shelter, creates shaded areas, and leaches tannins into the water, which helps to lower pH and soften the water naturally. Dried Indian almond leaves (Terminalia catappa) or oak leaves scattered across the substrate add to this effect and also provide a surface for biofilm and microfauna to colonise, which the catfish will graze on.

Live plants are not essential but can be included if the keeper is willing to select species tolerant of soft, acidic conditions and lower light levels. Java fern (Microsorum pteropus), various Anubias species, and floating plants such as Amazon frogbit (Limnobium laevigatum) are all suitable. Dense floating plant cover helps to diffuse light and create the shaded conditions these fish would experience in their natural habitat.

Lighting should be subdued. Bright overhead lighting without shade will stress most blackwater species. Floating plants, tannin-stained water, and careful placement of overhead cover all help to keep light levels comfortable.

Water parameters

Given the extreme softwater, blackwater origin of this species, maintaining appropriate water chemistry is arguably the single most important aspect of its care. The parameters below reflect the conditions of its native Rio Icana habitat as closely as practical in a home aquarium.

The low pH and negligible hardness of the Rio Negro system mean that this species is unlikely to thrive in hard, alkaline tap water. Keepers in areas with hard water will almost certainly need to use reverse osmosis (RO) water, remineralised very lightly (or not at all, depending on the target parameters) to achieve suitable conditions. A TDS (total dissolved solids) reading below 50 ppm is a reasonable target for replicating upper Rio Negro conditions.

Maintaining stable, very low pH can be challenging. At such low mineral content, the water has very little buffering capacity, meaning pH can fluctuate rapidly if not managed carefully. The use of botanical materials (leaves, driftwood, alder cones) helps to buffer the water naturally with organic acids. Some keepers use peat filtration or commercially available blackwater extracts to achieve and maintain these conditions. Whichever method is used, consistency is more important than hitting an exact number. A stable pH of 5.5 is far better than one that swings between 4.5 and 6.5.

Nitrate should be kept as low as possible, ideally below 10 ppm. Fish from nutrient-poor blackwater systems are generally less tolerant of nitrate accumulation than species from more mineral-rich environments. Regular partial water changes using appropriately conditioned water are essential.

Filtration and equipment

Filtration should be efficient but gentle. Corydoras and Brochis species are not strong swimmers and do not appreciate powerful currents. A sponge filter is an excellent choice for smaller setups, providing good biological filtration with minimal flow. For larger tanks, a small external canister filter with the outlet fitted with a spray bar or lily pipe can work well, provided the flow rate is kept moderate. Internal power filters can also be used if the flow is adjustable and can be turned down sufficiently.

Biological filtration is the priority. In very soft, acidic water, the nitrogen cycle can behave somewhat differently from what keepers accustomed to neutral or alkaline water might expect. Nitrifying bacteria are less efficient at very low pH values (below about 6.0), which means that biological filtration may not process ammonia and nitrite as rapidly as in harder, more alkaline setups. This makes it even more important to avoid overstocking, to feed carefully, and to maintain a mature filter with a well-established bacterial colony. Some keepers of extreme blackwater tanks find it helpful to supplement standard biological media with additional surface area, such as ceramic rings or sintered glass media.

A heater is necessary to maintain the warm temperatures this species requires. A reliable, adjustable heater with a thermostat is essential. Given the target range of 24 – 28 °C (75 – 82 °F), most standard aquarium heaters will be suitable. A separate thermometer (digital or glass) should be used to verify the heater’s accuracy.

An air pump driving a sponge filter or a separate airstone can be beneficial, both for oxygenation and for providing gentle surface agitation. Corydoras and Brochis species are facultative air breathers, meaning they can gulp air from the surface and absorb oxygen through their intestinal lining. Occasional trips to the surface for air are normal and not a sign of distress, but frequent, frantic surface-gulping may indicate poor water quality or insufficient dissolved oxygen.

Diet and feeding

Specific dietary studies for Brochis incolicana in the wild have not been published, so its precise natural diet is not documented. However, based on what is known about closely related species and the ecology of its habitat, it is almost certainly an omnivorous benthic forager, feeding on small invertebrates, insect larvae, detritus, biofilm, and organic matter found in and on the substrate.

In captivity, a varied diet is recommended. High-quality sinking pellets or wafers designed for bottom-dwelling catfish should form the staple. These should be supplemented regularly with frozen or live foods such as bloodworm, daphnia, brine shrimp, and tubifex. Live foods are particularly valuable for conditioning fish and for encouraging natural foraging behaviour. Blanched vegetables (courgette, cucumber, or spinach) can be offered occasionally, though not all individuals will accept them readily.

Feeding should take place in the evening or after lights-out, as Corydoras and Brochis species tend to be most active during low-light periods. It is important to ensure that food actually reaches the bottom of the tank and is not consumed entirely by midwater or surface-dwelling tank mates before the catfish have a chance to feed. Using dedicated sinking foods and feeding after the lights go off are both effective strategies for ensuring the catfish get their fair share.

Overfeeding should be avoided, as uneaten food decaying on the substrate will quickly degrade water quality, particularly in the soft, low-pH conditions this species requires. Feed only as much as the fish will consume within a few minutes, and remove any uneaten food promptly.

Behaviour and temperament

Like virtually all Corydoras and Brochis species, B. incolicana is a peaceful, social catfish. It is not aggressive towards tank mates and poses no threat to other fish, invertebrates, or plants. It spends the majority of its time on or near the substrate, foraging through the sand with its barbels and resting in sheltered spots among driftwood or leaf litter.

Social grouping is important. These fish should be kept in groups of at least six, and larger groups are better. In too-small groups, individuals tend to be shy, stressed, and less active. In a well-sized group, they are more confident, more visible, and more likely to display their full range of natural behaviours, including group foraging, resting in contact with one another, and the characteristic darting to the surface for a gulp of air.

Activity levels tend to increase during low-light periods, particularly at dawn and dusk. During bright daylight hours, the fish may spend much of their time resting in shaded areas. This is normal behaviour and not a cause for concern, provided the fish are active and feeding during their preferred periods.

Detailed behavioural studies specific to B. incolicana have not been published. The behavioural descriptions above are based on general Corydoras and Brochis behaviour, which is highly conserved across the group. There is no reason to expect this species to differ significantly in temperament from its close relatives, but it is worth noting that species-specific behavioural nuances may exist that have simply not been documented.

Tank mates

Choosing tank mates for Brochis incolicana requires careful consideration of the extreme water parameters this species needs. Any potential companion must be able to thrive in very soft, acidic, warm water. This immediately rules out a large number of common aquarium species. The best candidates are other fish from similar blackwater Amazonian habitats, particularly the Rio Negro basin and its tributaries.

Good tank mates

• Cardinal tetra, a classic Rio Negro species perfectly suited to the same soft, acidic conditions
• Green neon tetra, another small Rio Negro tetra that thrives in very soft, warm water
• Rummy-nose tetra, a peaceful shoaling fish well suited to blackwater setups
• Ember tetra, a tiny, peaceful characin comfortable in soft, acidic conditions
• Chocolate gourami, a quiet, soft-water labyrinth fish that appreciates similar conditions
• Pencilfish, small, peaceful surface and midwater dwellers from similar habitats
• Otocinclus, gentle algae-grazing catfish that share the same water preferences
• Apistogramma, dwarf cichlids from soft, acidic South American waters; choose less aggressive species
• Hatchetfish, surface-dwelling fish from blackwater habitats that occupy a different zone in the tank
• Pygmy corydoras, a tiny Corydoras species that does well in similar conditions and adds activity to the lower levels

Fish to avoid

• African cichlids, require hard, alkaline water completely incompatible with this species
• Goldfish, coldwater fish with entirely different requirements in every respect
• Guppy, prefer harder, more alkaline water and would not thrive in these conditions
• Molly, require hard, often slightly brackish water; completely unsuitable
• Platy, another livebearer needing harder, more alkaline water
• Oscar, far too large and aggressive to house with small, peaceful catfish
• Red-tail catfish, a massive predator that would eat this species
• Tiger barb, a boisterous fin-nipper that may stress quieter tank mates, and prefers different water chemistry
• Common pleco, grows far too large and produces excessive waste for the delicate conditions required
• Jack Dempsey, an aggressive cichlid entirely unsuitable as a companion

Breeding

Specific breeding reports for Brochis incolicana in captivity are extremely limited. This species is rarely kept, rarely imported in numbers sufficient for breeding groups, and there are no detailed published accounts of successful captive spawning that could be cited with confidence. What follows is therefore a combination of the little that is known and reasonable inference from breeding protocols used for related Corydoras and Brochis species. It should be read with that caveat firmly in mind.

In most Corydoras species, breeding is triggered by environmental changes that simulate the onset of the rainy season: a significant water change with slightly cooler, softer water, combined with a drop in barometric pressure and increased food availability. The spawning itself typically involves the well-known “T-position,” where the male and female clasp together, the female cups her ventral fins to receive a small clutch of eggs, and then deposits them on a chosen surface such as the aquarium glass, broad leaves, or other smooth surfaces. This cycle repeats until the female has deposited all her eggs, which may number from a few dozen to over a hundred depending on the species.

Whether B. incolicana follows this exact pattern has not been documented in published sources. Given its placement within the broader Corydoras/Brochis lineage, it is reasonable to expect broadly similar reproductive behaviour, but the specific triggers, clutch sizes, egg incubation times, and fry-rearing requirements for this species remain undocumented.

For anyone attempting to breed this species, the most sensible approach would be to start with a well-conditioned group of at least six to eight individuals, maintained in optimal water conditions with a varied, high-quality diet rich in live and frozen foods. Simulating seasonal changes through gradual cooling of replacement water during water changes, increased feeding, and perhaps adjusting the photoperiod may help to stimulate spawning behaviour. Any eggs laid should be removed to a separate hatching container to prevent predation by adults, which is common in Corydoras species.

Given the rarity of this species in the hobby, any successful breeding would be a significant achievement and well worth documenting and sharing with the broader fishkeeping community.

Common diseases and health

Brochis incolicana is susceptible to the same range of health issues that affect other Corydoras and Brochis species. Barbel erosion is one of the most commonly encountered problems in captive Corydoras, caused by keeping fish on sharp or dirty substrates. The barbels become shortened, damaged, or infected, impairing the fish’s ability to forage. Prevention is straightforward: use fine, smooth sand, keep the substrate clean, and maintain excellent water quality. If barbel damage is noticed, improving substrate and water conditions will often allow regeneration over time, though severe damage may be permanent.

Bacterial infections, including fin rot and skin infections, can occur when water quality deteriorates or when fish are stressed by inappropriate conditions. In the very soft, acidic water this species requires, standard aquarium medications may behave differently than in harder, more alkaline water. Some medications, particularly those containing copper or certain dyes, can be more toxic at low pH and hardness. Keepers should research any medication carefully before use and consider reducing doses in extreme softwater conditions. Salt treatments, commonly recommended for many freshwater fish diseases, should be used with great caution or avoided entirely, as most blackwater species have very low salt tolerance.

Ichthyophthirius multifiliis (white spot disease) can affect this species as it can any freshwater fish. The higher end of the temperature range (28 °C / 82 °F) may help to accelerate the parasite’s lifecycle and can be used as part of a treatment strategy, but raising temperature further in an already warm tank requires caution to avoid oxygen depletion. Maintaining pristine water quality, avoiding temperature fluctuations, and quarantining new arrivals are the best preventive measures. As with all rarely imported wild-caught fish, new specimens should be quarantined for at least two to four weeks before being added to an established community, to allow any latent infections or parasites to manifest and be treated before they can spread.

Frequently asked questions

What does C001 mean?

C001 is the C-number assigned to this species by DATZ magazine in 1993. It was the very first Corydoras to receive a C-number, a system designed to catalogue undescribed or newly imported Corydoras-type catfish for identification purposes within the hobby. The number has no taxonomic standing but remains widely recognised among catfish enthusiasts.

Is it Corydoras or Brochis?

As of 2024, the species has been reclassified as Brochis incolicana following a major taxonomic revision by Dias et al. It was previously known as Corydoras incolicana, and this older name remains in widespread use in the aquarium trade. Both names refer to the same fish. The reclassification reflects updated phylogenetic understanding rather than any change in the fish itself.

Where does this fish come from?

The type locality and confirmed range is the Rio Icana in the upper Rio Negro basin, Amazonas, Brazil. Some online retailers list Peru or Colombia as the origin, but these attributions conflict with the type locality and published collection records. The Rio Icana, Brazil should be considered the reliable origin.

Can I keep this fish in hard tap water?

This is not recommended. Brochis incolicana originates from extremely soft, acidic blackwater conditions. Hard, alkaline tap water is far outside its natural range and is likely to cause chronic stress and health problems. Keepers in hard water areas should use reverse osmosis water, remineralised only very lightly, to achieve appropriate conditions.

How many should I keep?

A minimum group of six is recommended, as with most Corydoras and Brochis species. Larger groups are preferable and will result in more confident, active, and natural behaviour. Keeping fewer than six is likely to produce shy, stressed fish that spend most of their time hiding.

Has this species been bred in captivity?

Documented breeding reports for this species are extremely scarce. While it is likely that breeding is possible using techniques similar to those successful with related Corydoras species, there are no detailed published accounts of captive spawning that can be referenced with confidence. This remains one of the many gaps in the available information about this fish.

Is this species endangered?

The IUCN lists Brochis incolicana as Data Deficient, meaning there is insufficient information to make a reliable assessment of its conservation status. This does not mean it is safe or threatened; it simply means we do not know. Given the remoteness of its habitat in the upper Rio Negro basin, detailed population surveys have not been conducted.

Why is this guide shorter than some other species profiles?

Because this species is genuinely under-documented. Rather than padding the guide with information borrowed from other species and presented as if it applies specifically to B. incolicana, this guide aims to be honest about what is and is not known. Where species-specific data is unavailable, this is stated plainly.

Related guides

• Bronze corydoras
• Pygmy corydoras
• Sterbai corydoras
• Panda corydoras
• Emerald catfish
• Cardinal tetra
• Otocinclus