Masked Corydoras (Hoplisoma metae)

The Masked Corydoras is a small, peaceful South American armoured catfish with a dark band through the eye and a second dark marking running over the back towards the tail. Its currently accepted scientific name is Hoplisoma metae. Many aquarists, shops and older references still know it as Corydoras metae, so both names are included here to make the identity clear without repeating either unnaturally.

This species is best for a mature tropical aquarium with a smooth substrate, clean oxygen-rich water and a proper same-species group. It spends much of the day searching the bottom together, but it is not an algae eater and should never be expected to live on leftovers. Choose the available size, then set the quantity for the number of individual fish required. For natural social behaviour, plan for at least six Masked Corydoras and make sure the aquarium has enough floor space for the whole group.

What you are buying

This listing is priced per individual fish. Use the size selector to choose the available body-size band and the quantity control to build the group you need. The measurements describe the approximate size of the fish supplied, not its final adult size. Natural variation is expected in live animals, and colour can look paler immediately after transport before returning as the fish settles.

A single Masked Cory may survive, but solitary keeping does not meet the species' social needs. A group of six is the practical minimum, while eight or more usually produces more confident daytime foraging and a broader range of natural interactions. If the aquarium cannot house that group comfortably, choose a smaller species or delay the purchase until a suitable tank is ready.

Identity, current name and the Bandit Cory mix-up

The 2024 phylogenomic revision of Corydoradinae resurrected several genera that had long been placed within Corydoras. Under that classification, the Masked Corydoras is Hoplisoma metae. The name Corydoras metae remains important because it appears throughout older books, care guides, stock lists and aquarium searches. It is a former combination for the same species, not a different fish.

Common names require more care. "Bandit Cory" is used for more than one similar-looking fish, especially Hoplisoma metae and Hoplisoma melini. On the Masked Cory, the dark dorsal marking crosses the top ridge of the back. On H. melini, often called the False Bandit Cory, the diagonal flank stripe generally leaves the top ridge pale and continues towards the lower part of the tail. Pattern quality, viewing angle and stress colour can complicate identification, so the scientific identity should take priority over a shared trade name.

Feature	Masked Cory, H. metae	False Bandit Cory, H. melini
Eye marking	Dark mask through the eye	Dark mask through the eye
Back marking	Dark band crosses the ridge of the back	Upper ridge is usually pale between the diagonal markings
Tailward stripe	Broad dark saddle runs towards the tail base	Diagonal stripe commonly continues towards the lower caudal area
Buying advice	Use the scientific name and inspect the back pattern rather than relying on "Bandit Cory" alone.

Natural range and what it means in an aquarium

Eschmeyer's Catalog of Fishes records this species from the Meta River basin in Colombia, where the original type locality was given as Barrigona, or Berrigon, in the Rio Meta drainage. FishBase also lists it as a freshwater, bottom-associated species from that basin. This restricted geographic identity is more useful than generic claims that it comes from all over South America.

A home aquarium cannot reproduce an entire river system, and it does not need to. The practical lessons are to provide warm freshwater, a clean bottom, shaded structure, oxygen and a varied diet of small foods that reach the substrate. Smooth wood, leaf-shaped cover and rooted or attached plants can create a calm lower level while open patches let the group search for food.

The species' natural range should not be used to justify sudden changes in temperature or chemistry. Seasonal river changes happen across large volumes of water and are not the same as an abrupt swing in a glass aquarium. Stability, low nitrogen waste and patient acclimation are safer than repeatedly adjusting pH to chase a precise wild-water number.

Tank size, footprint and group planning

Floor area matters more than height because Masked Corydoras feed, rest and interact near the bottom. A mature 60-litre aquarium with a broad footprint can be a tightly managed starting point for six small fish, but 75 litres or more is the more forgiving recommendation. A tank around 60 cm long gives a group room to forage without crowding every feeding point. Choose a larger footprint for eight or more corys, a busy community, or other bottom-dwelling species.

Volume alone can mislead. A tall, narrow aquarium may hold the same litres as a long tank but provide much less usable substrate. Before ordering, mark out where the open feeding area, plants, wood, filter intake and shelters will sit. The group should be able to move around the whole lower level without being trapped in one corner by territorial tank mates.

Planned setup	Starting point	What to check
Six Masked Corydoras, lightly stocked	75 litres recommended	Broad footprint, mature filter and several open feeding patches
Eight to ten Masked Corydoras	90 litres or more	More floor area and enough food access for every fish
Community with another bottom species	Increase volume and footprint	Separate territories, compatible water and no feeding competition
Tall display tank	Assess footprint, not litres alone	Usable bottom area may be smaller than expected

For help comparing the full group, browse the Corydoras collection and read the Corydoras care guide before combining species.

Water parameters and aquarium maturity

FishBase gives a species range of 22–26°C, pH 6.0–8.0 and 2–25 dH. Those figures describe biological tolerance, not a reason to move a fish rapidly between extremes. For routine aquarium care, 22–26°C, pH 6.0–7.5 and soft to moderately hard water are sensible targets. Stable, dechlorinated tap water within the broader range is often safer than chemically altered water that changes at every water change.

Parameter	Working range	Good practice
Temperature	22–26°C	Keep steady; match tank mates to the same long-term range
pH	6.0–7.5 practical target	Avoid abrupt correction with bottled pH products
Hardness	Soft to moderately hard is straightforward	Know the source water and acclimate gradually
Ammonia	0 mg/L	Any detectable result needs immediate investigation
Nitrite	0 mg/L	Any detectable result is unsafe
Nitrate	Keep low and stable	Control with stocking, feeding, plants and regular water changes

Add these fish only after the nitrogen cycle is established. A newly filled tank is not mature because the water looks clear. Test ammonia and nitrite, verify that both remain at zero, and confirm the filter can process the aquarium's normal feeding load. Because corys are in constant contact with the lower level, deteriorating substrate and trapped food can affect them before an upper-water fish shows obvious trouble.

Weekly partial water changes are a sound baseline, but the exact schedule depends on stocking and test results. Match replacement water temperature, use a suitable dechlorinator and avoid cleaning all biological filter media under untreated tap water. Rinse reusable media gently in removed aquarium water when flow begins to fall.

Substrate, barbels and bottom hygiene

Fine aquarium sand is the easiest substrate for observing natural sifting behaviour. The fish take small mouthfuls, investigate edible particles and release the substrate through the mouth and gill area. Very smooth, rounded fine gravel can also be used, but sharp, coarse or jagged material should be avoided.

Sand alone does not guarantee healthy barbels. Persistent dirt, uneaten food, poor water quality and abrasive surfaces can all contribute to damaged mouthparts. Keep the bed shallow enough to maintain, stir only where appropriate for the chosen substrate, and remove visible waste without turning every clean into a complete disturbance. Healthy barbels should look even and intact, not shortened, reddened or fuzzy.

Filtration, oxygen and normal air-gulping

Use a mature biological filter with enough circulation to prevent stagnant areas, but do not force the group to fight a powerful jet whenever they feed. A sponge filter, protected internal filter or suitably baffled external return can work. Guard intakes where a small fish could be trapped, and keep the surface moving so gas exchange remains effective.

Masked Corydoras are facultative air breathers. An occasional dash to the surface for a gulp of air can therefore be normal. Repeated frantic surfacing by the whole group is different: check temperature, oxygenation, ammonia, nitrite, filter flow and any recent chemical addition. Warm water holds less dissolved oxygen, so a heatwave or medication course can expose a marginal system quickly.

Do not add salt as a routine tonic. Corydoradinae can be more sensitive than many community fish to salt and to some medications, especially when products are combined. Diagnose the problem, check the label for catfish restrictions, calculate actual water volume and seek qualified aquatic-veterinary guidance when the condition is uncertain. Remove carbon only when the chosen treatment instructions require it, and increase aeration if the medicine reduces available oxygen.

Plants, wood, lighting and a usable layout

Plants are useful for shade and visual security, but this species does not require a densely planted aquarium. Attach Anubias or Java fern to smooth wood, use rooted Cryptocoryne around the edges, and leave open substrate at the front or centre. Floating plants can soften strong light as long as they do not seal the whole surface and restrict gas exchange.

Create more than one sheltered zone so a dominant or nervous tank mate cannot control the only retreat. Smooth wood and rounded stones are safer than sharp resin ornaments. Check every cave opening against the adult body depth; a cory should not be able to wedge itself while turning. The best layout looks attractive from above the substrate but still leaves a continuous route around the lower level.

A seven to nine hour lighting period is sufficient for many planted community tanks. If the fish hide whenever the main light comes on, add shade, introduce a gentle ramp through room lighting, and reassess boisterous tank mates. Constant hiding is information about the environment, not proof that the species is naturally nocturnal.

Social behaviour and what a settled group looks like

These corys are social rather than tightly schooling every minute. A settled group may spread out to feed, rest in small clusters, then gather and move together. Short bursts along the glass can occur after a water change or during courtship. New arrivals may stay close for security while they learn the tank.

Same-species numbers matter because a mixed collection of one fish from six different cory species is not equivalent to six conspecifics. Different species may associate, but they use their own visual and chemical cues. Keep at least six Masked Corydoras together even when another cory group is present.

Signs of a comfortable group include level swimming, intact fins and barbels, regular substrate searching, steady breathing, rounded but not swollen bellies and a prompt response to food. Warning signs include clamped fins, isolation, persistent rapid breathing, red patches, a pinched abdomen, repeated loss of balance or failure to compete at feeding time.

Tank mates and community compatibility

Choose peaceful species that accept the same temperature and water chemistry. Small tetras, pencilfish, hatchetfish and calm rasboras can occupy the middle and upper levels without competing heavily for the bottom. Peaceful dwarf cichlids may work in a suitably large, structured tank, but breeding cichlids can defend the floor aggressively. Compatibility depends on tank dimensions, group sizes and individual behaviour, not just a species list.

Potential companion	General fit	Important condition
Small peaceful tetras	Usually good	Make sure sinking food reaches the cory group
Pencilfish and hatchetfish	Usually good	Use a secure lid and compatible water
Calm rasboras	Often suitable	Match temperature and hardness
Other Corydoradinae	Possible in larger tanks	Still keep a full group of each species
Dwarf cichlids	Case by case	Provide space; breeding adults may guard the bottom
Adult dwarf shrimp	Often coexist	Very small shrimplets may be eaten opportunistically
Large or aggressive cichlids	Avoid	Risk of injury, predation and constant stress
Boisterous bottom feeders	Usually avoid	Competition can leave the corys underfed

For another boldly marked species, compare the Duplicareus Corydoras. The Panda Cory Catfish is a useful smaller-patterned comparison, while a Corydoras mixed selection can suit aquarists who understand that each species still needs appropriate social numbers.

Diet and feeding without relying on scraps

Masked Corydoras are omnivorous bottom foragers. A complete sinking pellet or soft wafer made for small catfish should form the staple, supported by appropriately sized frozen or live foods such as daphnia, cyclops, brine shrimp, bloodworm and small worms. Rotate foods rather than feeding one rich item every day.

Algae wafers are not automatically a complete diet, and this fish is not a solution for algae on glass. It will investigate edible material on the bottom but cannot live on waste produced by other fish. In a community aquarium, watch a full feeding to confirm that food reaches every cory before faster fish take it.

Food type	Role	How to use it
Complete sinking micro-pellet	Daily staple	Distribute across two or more feeding spots
Soft catfish wafer	Staple or rotation food	Break to group-sized portions; remove uneaten remains
Frozen daphnia or cyclops	Variety	Offer small portions that reach the bottom
Frozen or live bloodworm	Protein-rich supplement	Use in rotation, not as the only food
Brine shrimp	Conditioning and variety	Rinse when appropriate and avoid overfeeding
Leftovers from other fish	Not a diet	Target-feed the cory group deliberately

Feed one or two small meals each day, adjusting to body condition, temperature and community competition. A portion should be cleared promptly without leaving food to decay overnight. If fish are thin despite eating, investigate competition, parasites and water quality rather than simply adding larger amounts that pollute the tank.

New arrivals may feed more confidently after the main lights dim. Place a small amount near cover, then observe quietly. Once settled, many groups learn the normal routine and forage openly in daylight.

Adult size, sex differences and lifespan

FishBase records a maximum of 4.8 cm standard length. Standard length excludes the tail fin, so the total length seen in an aquarium can be closer to 5–6 cm. Avoid advertising a fixed adult size for every individual because sex, age, feeding and measurement method create variation.

Mature females are usually larger and broader through the abdomen, especially when viewed from above. Males tend to remain slimmer. Sexing small juveniles is unreliable, and this listing does not promise a chosen sex unless a variant explicitly says so.

Well-kept corys are long-term fish. Aquarium reports commonly place their potential lifespan in the region of five to ten years, but no lifespan can be guaranteed. Mature filtration, a suitable group, balanced food, stable water and early attention to illness influence longevity more than a promotional maximum.

Health checks, quarantine and common warning signs

Before adding new fish, prepare a quarantine plan whenever possible. A separate, cycled observation tank lets you confirm feeding, faeces, respiration and external condition without exposing an established community. Quarantine equipment should not be shared wet between tanks unless it is properly disinfected.

What you see	What it may mean	First response
Occasional single air gulp	Normal facultative air breathing	Observe the wider group and water conditions
Whole group repeatedly gasping	Low oxygen, heat, toxins or gill irritation	Test water, increase aeration and investigate immediately
Short or inflamed barbels	Abrasion, dirty substrate or infection	Improve hygiene and seek a diagnosis before treatment
Pinched belly	Underfeeding, competition or internal disease	Observe targeted feeding and quarantine if needed
White spots or excess mucus	Possible parasite or irritation	Confirm symptoms; use a catfish-safe treatment only as directed
Redness or ulcers	Water-quality injury or infection	Check ammonia and nitrite, isolate where appropriate and seek expert help

Never mix medicines casually. Many products share active ingredients, and combining them can produce an overdose even when each bottle is used at its stated rate. Do not use antibiotics without a justified diagnosis. For serious or persistent symptoms, consult an aquatic veterinarian or experienced fish-health professional.

Arrival and acclimation

Prepare the aquarium before the delivery day. Test the water, switch off intense lighting, check that the filter and heater are stable, and make sure current residents are not likely to attack a new bottom fish. Read the instructions supplied with the order before opening the bags because prolonged exposure to opened transport water can change its chemistry.

1. Inspect the sealed package and fish promptly on arrival.
2. Follow the supplied temperature and transfer instructions rather than extending acclimation automatically.
3. Move the fish with clean equipment and avoid adding transport water to the display aquarium where practical.
4. Keep lighting low and do not force a large first meal.
5. Observe breathing, balance and group behaviour over the first hours.

Our acclimation timer can help organise the process, while the water matcher is useful when checking whether planned tank mates share compatible conditions.

Breeding behaviour and egg care

Condition a mature group with varied foods and excellent water quality. A larger water change with slightly cooler replacement water is often used by breeders to imitate a seasonal trigger, but the change must remain within a safe range. Spawning is more likely when both sexes are present and the adults are well fed without becoming overweight.

Corydoradinae show the characteristic T-position during courtship. FishBase describes the female holding a small group of eggs between the pelvic fins before attaching the adhesive eggs to a chosen surface. The sequence repeats as additional eggs are laid. Eggs may be placed on glass, plant leaves, spawning mops or filter housing.

Adults may eat eggs, so breeders commonly move either the adults or the eggs after spawning. A separate container needs clean water with matching chemistry and gentle movement around the eggs. Remove clearly fungused eggs with clean tools. Hatching time depends on temperature, and newly hatched fry should not be fed until the yolk sac is largely absorbed.

First foods must be small enough for the fry and present where they can find them. Microworms, newly hatched brine shrimp and suitable powdered fry foods can be used as growth allows. Feed tiny amounts, siphon waste carefully and make frequent small water changes with matched water. Stable cleanliness is more important than forcing rapid growth.

Conservation and responsible ownership

FishBase currently displays the species as Vulnerable based on the cited 2020 IUCN assessment. That status concerns the wild population and should not be turned into an unsupported claim about the origin of an individual shop fish. This listing does not describe stock as captive bred unless that origin has been confirmed for the batch.

Responsible ownership means buying only the group the aquarium can support, preventing release into the wild, maintaining the fish for its full life and avoiding casual breeding without homes for the offspring. Never release aquarium fish, plants or water into local waterways.

A practical weekly care routine

A repeatable routine is more useful than reacting only when the fish look unwell. Begin each maintenance session by watching the aquarium before disturbing it. Check whether the whole group is visible, whether breathing is even, and whether any fish has separated from the others. Look at the barbels, fins, abdomen and eyes from more than one angle. A change from the group's normal behaviour can be an early warning even when a test result still looks acceptable.

Task	Typical frequency	What good practice looks like
Observe the group	Daily	Count fish, compare breathing and confirm each one feeds
Remove uneaten food	After feeding when needed	No soft food remains trapped under wood or plants
Test water	Weekly at first, then according to the established tank	Ammonia and nitrite stay at zero; nitrate trend is understood
Partial water change	Usually weekly	Replacement water is dechlorinated and temperature matched
Clean exposed substrate	During water changes	Visible waste is removed without stripping the whole tank at once
Check filter flow	Weekly	Surface movement remains steady and intakes are clear
Rinse reusable filter media	Only when flow or debris requires it	Media is handled gently in removed aquarium water
Inspect heater and thermometer	Weekly	Actual temperature agrees with the controller setting

Do not deep-clean the filter and substrate on the same day unless an emergency makes it necessary. Preserving stable biological filtration matters more than making every surface look sterile. Rotate the parts of the bottom that receive more detailed cleaning, and keep a simple record of test results. Trends are easier to act on than isolated numbers remembered from several weeks apart.

Plant leaves and wood create useful shelter but can hide food. Use a small torch to inspect behind decor after feeding and during maintenance. If one corner repeatedly collects debris, adjust circulation gently or change the layout rather than simply increasing filter power across the entire bottom.

The first seven days after arrival

The first week should be quiet and predictable. Keep the normal day-night cycle, avoid rearranging the aquarium, and resist adding other new fish immediately. A new group may spend more time under cover, but it should gradually begin exploring and responding to food. Compare each individual at the same time every day so a thin or withdrawn fish is not hidden by the activity of the rest.

1. Arrival day: follow the supplied acclimation process, keep lights low and offer only a very small meal after the fish have settled.
2. Days two and three: confirm every fish can reach sinking food and check ammonia and nitrite if the stocking load has changed materially.
3. Days four and five: look for improving colour, relaxed fins and broader use of the substrate. Recheck any individual that remains isolated.
4. Days six and seven: review feeding portions, remove any recurring waste traps and record the group's normal behaviour for future comparison.

Temporary paleness can follow transport, and a shy fish may need time to join the group. Persistent rapid breathing, rolling, inability to remain upright, obvious injury or failure to feed requires prompt investigation. Test the water first, preserve clear photos or video, and contact support within the guarantee terms when an arrival concern is present.

Do not medicate the entire display tank merely because a new fish hides on day one. Medication can stress fish, plants and biological filtration, and it may conceal the actual cause. Observation, water testing and a prepared quarantine tank give much better information.

Common care mistakes to avoid

Mistake	Why it causes trouble	Better approach
Buying one or two fish	Small numbers are more likely to remain nervous and hide	Plan space and budget for at least six before ordering
Using the group as a cleanup crew	Scraps do not provide a balanced diet and decaying food pollutes the bottom	Target-feed complete sinking foods and maintain the aquarium normally
Choosing sharp decorative gravel	Repeated contact can damage mouthparts and restrict natural sifting	Use fine sand or genuinely smooth, rounded fine gravel
Adding fish to an uncycled tank	Ammonia and nitrite can rise before the aquarium looks dirty	Establish and test biological filtration before purchase
Keeping only a mixed-species assortment	Different cory species do not fully replace same-species companions	Maintain a suitable group of each species represented
Feeding only after the lights go out	Problems and competition are harder to observe	Use some targeted low-light feeds but regularly watch the group eat
Chasing an exact pH with chemicals	Repeated swings can be more stressful than stable water within range	Understand the source water and make changes gradually when truly needed
Treating every surface dash as disease	Occasional air breathing is normal for the group	Judge frequency, the whole group's behaviour and measured water quality
Assuming a tall tank has enough room	Litres may be high while usable floor area remains limited	Compare footprint, stocking and feeding zones

Pre-purchase checklist

Complete this check before selecting a delivery date. It protects the fish and prevents rushed changes after the parcel is already on the way.

• The aquarium is fully cycled, with zero ammonia and zero nitrite.
• The normal temperature stays within 22–26°C.
• The tank has a suitable footprint and capacity for at least six same-species fish.
• The substrate is smooth, the bottom is clean, and open feeding areas remain available.
• Existing tank mates are peaceful, correctly sized and compatible with the same water.
• Sinking staple food and at least one suitable rotation food are ready.
• A secure lid, protected filter intake and adequate surface movement are in place.
• The delivery can be received promptly, and the guarantee instructions have been read.
• A quarantine or observation plan is available for new livestock.

If any essential item is missing, postpone the order rather than improvising around live fish. A well-prepared tank is the strongest start for confident feeding, intact barbels and stable group behaviour.

UK delivery, guarantee and first-order discount

Live fish are packed for tracked UK delivery using insulated materials and seasonal temperature protection where required. Delivery availability, dates and any location restrictions are shown through the ordering process. Review the full live fish delivery information before choosing a date.

Eligible livestock orders are covered by our Live Arrival Guarantee. The evidence window and claim steps matter, so read the returns and Live Arrival Guarantee terms before delivery day and record the sealed parcel being opened as instructed. This gives the support team the evidence needed to help quickly if a problem occurs.

New customers can use code WELCOME10 for 10% off their first eligible order, subject to the promotion terms shown at checkout. The discount does not change the care requirement: order a complete social group only when the aquarium is ready for it.

Masked Corydoras questions

Scientific and care references

• Dias and colleagues (2024), phylogenomic revision and new Corydoradinae classification
• Eschmeyer's Catalog of Fishes, current status and Meta River distribution for Hoplisoma metae
• FishBase species summary, size, environment, water range and reproductive notes
• NCBI Taxonomy cross-reference for the accepted and former scientific names

Species data are checked against the linked references. Aquarium recommendations also apply welfare-focused husbandry judgement, so the practical tank and water advice is intentionally narrower than the broadest recorded biological tolerance.