Leopard Cory (Corydoras leopardus)

Recognise the Leopard Cory accurately

The Leopard Cory is a freshwater, bottom-living member of the armoured-catfish family Callichthyidae. FishBase records this fish from the western Amazon River basin and gives a maximum of 6.1 cm standard length for male or unsexed specimens. It is also a facultative air-breather, so access to the water surface must remain unobstructed. It suits keepers who can provide a mature, filtered community aquarium, maintain stable water and plan for a social Corydoras group.

FishBase now lists it as Brochis leopardus.

Separate it from a similar-looking cory

The Wikipedia summary of the Leopard Cory explains that it is often confused with the three line cory, Hoplisoma trilineatum. The clearest stated differences are the Leopard Cory’s longer, more pointed snout and its larger eventual size. Treat those as identification clues rather than promises about the precise pattern or proportions of an individual fish.

This is therefore not a combined identity covering several spotted cory species. Use the Leopard Cory name for this animal, allow for natural visual variation, and plan the aquarium around the 6.1 cm maximum recorded standard length. If you are assembling a tightly identified breeding project, compare the fish’s structure carefully rather than relying on a shared Julii-style trade label.

Choose the dispatch size from the live selector

One purchase supplies one animal of the selected option. The live selector uses the labels “3 - 3,5 cm” and “4 - 5 cm”; choose there when ordering rather than relying on a static statement elsewhere on the page. The size you select is the size supplied, not the adult size.

Dispatch length helps you plan the immediate introduction, but all choices require space for the same adult fish. A smaller selection does not describe a different species, a guaranteed age or a guaranteed life stage.

Build a group by adjusting quantity

Because each purchase unit is one animal, a planned group of five requires a quantity of five animals. Keep the selected size clear while changing quantity, and check the resulting order before completing it. This avoids mistaking one size choice for a multi-fish pack.

Sex is guaranteed only when the selected option explicitly states male or female. This Leopard Cory listing has no sex-guaranteed option.

Some gallery images are representative, based on reference photographs of this species, and none shows the exact animal supplied, so colours can look slightly different from the live animal.

Keepers comparing this fish with other members of the group can browse the current Corydoras collection. Make the final choice from adult size, social needs, water requirements and compatibility rather than pattern alone.

Plan around the adult size, group and water range

Three numbers shape the plan: a maximum recorded standard length of 6.1 cm, a group of at least five and an aquarium of at least 80 litres for a shoal of smaller Corydoras. The length comes from FishBase. OATA’s freshwater-catfish guidance supplies the group and aquarium figures. Those OATA figures are group guidance rather than a species-specific optimum.

For water, FishBase records 22–25°C, pH 6.0–8.0 and 2–25°dH for the species. OATA gives 22–27°C, pH 6.0–8.0 and 4–18°dH for freshwater catfish. Keep the aquarium at 22–25°C and pH 6.0–8.0, while using the narrower 4–18°dH hardness range. This stays inside the species figures and gives a practical routine range.

Check whether the plan fits

Do not treat 80 litres as permission to add five fish to any aquarium of that nominal volume. Check that the established community leaves enough biological capacity for the extra waste and enough usable lower-level space for the group to feed. A larger aquarium offers more stable environmental conditions, but it still requires filtration, testing and maintenance.

Prepare the aquarium before adding the group

Start with a mature, filtered aquarium rather than adding Leopard Corys while a new biological filter is still developing. The filter’s beneficial bacteria process toxic ammonia into toxic nitrite and then into safer nitrate. Both ammonia and nitrite must read zero before the fish enter, and those readings must remain zero after the group is added.

If this is your first setup, follow our guide to preparing and maturing a tropical aquarium before choosing livestock. Maturation is a biological process inside the filter; leaving an aquarium standing with water in it is not the same decision as establishing bacteria able to process fish waste.

Give the lower level structure and cover

OATA recommends live plants as cover for smaller or shy catfish and notes that many catfish appreciate shelter such as wood, pots or caves. Arrange cover without filling every part of the lower level. The group still needs accessible places where sinking food can be placed and where you can check that each fish is feeding.

• Filter: use a working, established biological filter suitable for the whole aquarium population.
• Cover: include plants and secure shelters that do not trap the fish.
• Surface: keep the route to the surface open because this species can breathe air facultatively.
• Feeding access: retain clear areas where sinking food can be observed and removed if uneaten.
• Maintenance access: arrange décor so settled waste can be reached with a siphon.

Choose an aquarium of at least 80 litres for the Corydoras shoal, then assess the existing inhabitants and filter capacity before adding the group. The larger environmental plan matters more than the height of the water alone: every inhabitant contributes waste, uses oxygen and competes for feeding opportunities.

Set stable water values before introduction

Keep the temperature between 22 and 25°C, pH between 6.0 and 8.0, and general hardness between 4 and 18°dH. Measure the aquarium rather than estimating from regional tap-water descriptions. The relevant values are those in the aquarium after conditioning, heating, décor and routine maintenance have influenced the water.

Our water chemistry guide explains what the common measurements mean, while the water matcher helps compare measured values with this working range. Test before purchase so that any adjustment happens gradually without a fish waiting to be introduced.

Use readings to make one decision at a time

Stability does not mean ignoring a poor result. It means correcting the underlying cause through measured, controlled changes instead of repeatedly pushing the value up and down. Test source water as well as aquarium water when a reading shifts unexpectedly; the comparison can show whether the change begins at the tap or inside the tank.

Record the result and date each week. A short sequence of readings reveals movement that a single test can miss, especially after a group is introduced and feeding increases. Temperature, pH and hardness determine whether the setup fits this fish, while ammonia, nitrite and nitrate show whether filtration and maintenance are keeping pace.

Protect the biological filter from avoidable damage

The RSPCA explains why aquarium filtration is vital: fish release toxic ammonia, and a working biological filter houses bacteria that convert it first to toxic nitrite and then to safer nitrate. Clear-looking water can still contain harmful dissolved waste, so appearance never replaces testing.

Check the filter for blockages during routine maintenance. If the media needs cleaning, rinse it lightly in aquarium water removed during the partial water change. Do not rinse established biological media under the tap, because chlorine or chloramine may kill part of the beneficial bacterial population.

Respond to a failed reading

1. When ammonia or nitrite is detected, stop adding fish and test again carefully.
2. Check whether the filter is running, whether flow is obstructed and whether feeding has left uneaten food.
3. Carry out the required maintenance with conditioned replacement water.
4. Continue monitoring until ammonia and nitrite return to zero.
5. Resume planned additions only when the aquarium is stable and the filter can carry the existing load.

Add livestock slowly because every extra fish and every increase in feeding asks the bacterial colony to process more waste. Adding a complete new population too quickly can create new tank syndrome, in which the filter cannot yet process the increased ammonia and nitrite. A mature filter is therefore not a permanently fixed capacity; it responds to the biological load placed on it.

Do not replace all established media simply because it looks stained. The useful bacteria live on the media, and preserving that colony is part of preserving water quality. Mechanical debris can be removed gently while leaving the biological system intact. Keep the filter running continuously, inspect it when flow changes, and use test results to judge performance.

Feed the group directly instead of relying on scraps

OATA describes Corydoras as omnivorous and recommends appropriate sinking foods for catfish. Their reputation as scavengers must not become a feeding plan. Food eaten by midwater fish or left to decay elsewhere in the aquarium does not ensure that the bottom-living group receives a complete meal.

Offer an appropriate sinking food once a day and give only what the fish can eat within a few minutes. Place it where the group can reach it and remain present long enough to see that more than the boldest fish are feeding. The food should be labelled for the needs of omnivorous aquarium catfish and sized so the selected fish can handle it.

Use observation to set the portion

Overfeeding does not compensate for competition. Uneaten food breaks down and releases waste, placing extra pressure on the biological filter. Solve competition by changing placement and checking the proposed community, not by scattering a large surplus through the aquarium.

Feed at a time when you can observe the full group. If a fish shows a reduced intake or loses interest in food, test the water and compare its behaviour with its normal pattern. A change in feeding response is useful early information, particularly when it appears alongside altered breathing, colour or swimming.

Use a repeatable weekly maintenance routine

Carry out a partial water change of 25% at least once every week. Treat replacement tap water with a conditioner that removes chlorine or chloramine before it enters the aquarium. Match the new water sensibly to the aquarium conditions so routine maintenance does not create an abrupt temperature or chemistry change.

Use a siphon to remove solid waste from accessible areas of the substrate. The aim is to remove settled debris and uneaten food without dismantling the aquarium or destroying the biological filter. Check beneath feeding points and around shelters, where waste may collect out of immediate view.

Test against clear limits

• Ammonia: zero mg per litre.
• Nitrite: zero mg per litre.
• Nitrate: no more than 20 mg per litre above the normal tap-water level.
• Temperature: 22–25°C.
• pH: 6.0–8.0.
• General hardness: 4–18°dH.

The nitrate limit is relative to the source water. For example, if conditioned tap water measures 10 mg per litre nitrate, the stated ceiling is 30 mg per litre in the aquarium. If tap water measures 20 mg per litre, the corresponding ceiling is 40 mg per litre. Use the measured baseline rather than assuming every household starts from zero.

Test at least weekly and add extra checks after a livestock addition, a filter interruption or an unexpected behaviour change. Write down the results. A log showing ammonia at zero, nitrite at zero and a stable nitrate pattern is more useful than trying to remember whether a colour looked slightly different the week before.

Finish by confirming that the filter is flowing, the surface remains accessible and no decaying food is trapped around the feeding area. This short sequence joins water changing, waste removal, testing and equipment inspection into one repeatable routine.

Introduce the fish slowly to a prepared aquarium

Arrange the aquarium and complete the water tests before the delivery day. Someone must be present to receive live fish, so use the confirmed delivery information for the order when planning. Keep the aquarium stable and avoid making an unrelated large change to décor, filtration or water chemistry immediately before introduction.

Follow the arrival sequence

1. Receive the parcel in person so the live fish is not left unattended.
2. Start filming while the parcel is still sealed and the outer box is visible.
3. Open the parcel in one continuous take and show the fish still inside the sealed bag.
4. Float the bag in the aquarium for 20–30 minutes.
5. Release the fish without pouring the bag water into the aquarium.

Read our delivery and Live Arrival Guarantee policy before the parcel arrives. Keep the continuous unboxing video and order number if you need to report a problem on the day of arrival.

Keep the biological increase controlled

A group adds several fish and increases the food entering the aquarium. OATA advises raising the aquarium population slowly because filter bacteria need to respond whenever fish numbers and feeding increase. If other livestock has just been added, wait for stable zero-ammonia and zero-nitrite readings rather than stacking another biological increase onto the same period.

Normal settling can include reduced activity or sheltering, but observation should remain active rather than intrusive. Check whether the group maintains appropriate swimming behaviour, whether breathing is steady and whether any fish shows damage. Offer only a controlled amount of sinking food once feeding begins, then remove excess instead of trying to draw a shy fish out with repeated portions.

During the first week, test ammonia and nitrite more often than the minimum weekly routine if anything changes. The correct response to a detectable reading is to protect water quality and filter function, not to add another fish to make the group look more confident.

Act on changes in health or behaviour early

Learn the normal behaviour and appearance of the group so a change is easy to recognise. Healthy fish should have clear, bright eyes, undamaged fins, intact external surfaces and swimming behaviour appropriate to the species. Appetite and body condition should remain consistent with the feeding routine.

Check these warning categories

An occasional trip to the surface can fit the species’ facultative air-breathing biology. A persistent change in surface use, breathing rate or swimming pattern still requires a water-quality check. Judge the change against the fish’s established pattern and the behaviour of the rest of the group.

Start with measured facts: temperature, pH, ammonia, nitrite, nitrate, recent maintenance and the timing of the last livestock addition. Do not apply a disease treatment merely because one sign resembles a condition seen elsewhere. Different water-quality and health problems can produce similar behaviour, while an unnecessary treatment may add another variable.

If you are concerned about a health change, test the water and contact us with the readings, timeline and visible signs. Photographs or a short video can help describe movement and appearance, but continue protecting water quality while guidance is sought.

Screen every proposed community before mixing fish

OATA describes Corydoras as suitable additions to community aquariums, while also warning that catfish compatibility varies. That supports a conditional community placement rather than a universal tank-mate list. Exact outcomes depend on the other animal’s adult size, behaviour, feeding method and water requirements, so assess the complete combination before purchase.

Apply the same screening order every time

1. Water: confirm that every proposed fish can live routinely at 22–25°C, pH 6.0–8.0 and 4–18°dH.
2. Adult size: compare eventual size rather than the dispatch measurements shown in the selector.
3. Predation: reject a mix where one animal could treat another as prey.
4. Aggression: check whether another inhabitant defends the lower level or repeatedly harasses feeding fish.
5. Food access: ensure the group can reach sinking food within its few-minute feeding period.
6. Biological capacity: confirm that the mature filter and maintenance routine can support the added waste.

A shared “community fish” description does not answer all six checks. Two animals may fit the same water range but compete strongly at feeding time, or they may feed differently while needing incompatible temperatures. The aquarium must satisfy the combination, not merely each animal viewed separately.

When assessing an existing aquarium, include every resident and its adult size. Also account for recent livestock additions because the filter bacteria may still be responding to the previous increase. If the intended mix cannot be assessed clearly from these factors, contact us with the aquarium volume, measured water values, full livestock list and intended group quantity.

Do not use resemblance as a compatibility test. Another spotted catfish may have different social behaviour or adult size. Likewise, a fish occupying the middle of the aquarium can still affect the cory group if it consumes all sinking food before the bottom fish reach it.

Protect the group’s access to food and space

The social requirement and compatibility plan must work together. OATA advises at least five Corydoras because individuals kept alone or in groups that are too small often become stressed. Adding five fish solves only the group-number decision; the aquarium must still accommodate the added biological load and allow all five to reach food.

Watch the first controlled feeding after introduction. If midwater residents intercept the food, place suitable sinking food at more than one accessible point. If a lower-level resident blocks a feeding area, reassess the mix rather than increasing the portion. A larger surplus raises the amount of waste without guaranteeing fair access.

Distinguish three different problems

Use shelter to give shy fish cover, but do not hide every feeding point behind décor. You need a clear view of the group during meals and enough access to siphon away uneaten food. This balance lets shelter support confidence without making condition and appetite difficult to assess.

Review compatibility again as fish grow. Dispatch sizes are immediate measurements, while adult planning must use eventual size. A mix that appears spacious around small fish may place a different demand on filtration and feeding access later. Plan for the group at up to 6.1 cm standard length rather than treating the selected dispatch size as permanent.

Answer the key questions before choosing

How big does the Leopard Cory get?

FishBase records the Leopard Cory at a maximum of 6.1 cm standard length. Plan the aquarium around that adult figure rather than the selected dispatch size.

What size aquarium does it need?

Use a mature, filtered aquarium of at least 80 litres for the shoal. OATA gives this as group guidance for smaller Corydoras, not a species-specific optimum.

How many Leopard Corys should I keep together?

OATA advises keeping Leopard Corys as part of a Corydoras group of at least five because fish kept alone or in groups that are too small often become stressed.

Does this fish suit beginners?

A beginner needs to provide a mature biological filter, zero ammonia and nitrite, stable water, a group of at least five and direct daily feeding with suitable sinking food.

What does the Leopard Cory eat?

OATA describes Corydoras as omnivorous. Give the Leopard Cory an appropriate sinking catfish food once daily, offering only what the group can eat within a few minutes.

What temperature and pH does it need?

Keep it at 22–25°C and pH 6.0–8.0; this is the overlap of FishBase’s species range and OATA’s freshwater-catfish guidance. Use 4–18°dH general hardness.

Is the Leopard Cory aggressive or likely to nip fins?

OATA places Corydoras in community aquariums, but compatibility still varies. Screen every mix for predation, harassment, lower-level conflict and whether the group can reach its food.

Which animals can it live with?

Consider community fish that share 22–25°C, pH 6.0–8.0 and 4–18°dH, cannot prey on or harass it, and allow the Corydoras group to reach sinking food.

How does the Leopard Cory arrive alive in the UK?

Start filming the sealed parcel before opening it, then continue in one take until the Leopard Cory is visible inside the sealed bag. Someone must be present to receive the parcel. Float the bag for 20–30 minutes, then release the fish without pouring bag water into the aquarium.

Consult the reference bibliography

• FishBase: scientific identity, family, western Amazon distribution, recorded environmental values, air-breathing biology and maximum standard length.
• Wikipedia species summary: natural-history identity and comparison with the three line cory.
• OATA freshwater-catfish guidance: aquarium water, Corydoras group planning, feeding, maintenance, introduction, observation and compatibility.
• RSPCA aquarium guidance: biological filtration and the processing of ammonia and nitrite.
• Tropical Fish Co delivery policy: arrival preparation, 20–30 minute floating instruction and Live Arrival Guarantee process.