Pink Corydoras

Pink Corydoras

Table of Contents


The Pink Corydoras, scientifically known as Corydoras axelrodi, is a fascinating species of fish that originates from the rivers and streams of South America. These small, yet vibrant fish have captured the attention of aquarium enthusiasts worldwide due to their striking appearance and unique characteristics.

In the realm of the aquarium trade, Pink Corydoras have gained immense popularity and have become highly sought after by fishkeepers. Their eye-catching pink coloration, coupled with their peaceful nature and hardy disposition, make them a favorite choice for both beginner and experienced aquarists.

These captivating fish have become a staple in community aquariums, adding a touch of vibrancy and elegance to any aquatic setup. Their active nature and social behavior make them a delight to observe, forming an integral part of the aquarium ecosystem.

The purpose of this article is to serve as a comprehensive guide on Pink Corydoras, offering valuable insights into their taxonomy, physical characteristics, natural habitat, behavior, feeding habits, breeding, aquarium care, common health issues, conservation status, and more. By delving into these aspects, we aim to equip aquarium enthusiasts with the knowledge and understanding necessary to provide optimal care and create a thriving environment for these captivating fish.

Throughout this article, we will explore the various facets of Pink Corydoras, shedding light on their unique attributes, requirements, and challenges. By doing so, we hope to foster a deeper appreciation for these remarkable fish and promote responsible ownership, ensuring their well-being and conservation for generations to come.

Taxonomy and Classification

Overview of the taxonomic classification of Pink Corydoras

Pink Corydoras, scientifically known as Corydoras axelrodi, belongs to the family Callichthyidae, commonly referred to as armored catfish. This family includes various species of small, bottom-dwelling freshwater fish known for their unique body armor and barbels. Within the family Callichthyidae, Pink Corydoras falls under the genus Corydoras.

Species name and origin of Corydoras axelrodi

The species name, Corydoras axelrodi, is named in honor of Dr. Herbert R. Axelrod, a renowned ichthyologist and pioneer in the aquarium fish trade. Dr. Axelrod played a significant role in popularizing and introducing many tropical fish species to the aquarium hobbyist community.

Corydoras axelrodi is native to the upper Orinoco River basin in Venezuela and Colombia, specifically in the regions of Puerto Ayacucho and Puerto Carreño. These areas are characterized by dense vegetation, slow-moving rivers, and sandy substrates, providing an ideal habitat for Pink Corydoras.

Common names associated with Pink Corydoras

Pink Corydoras is commonly referred to by its scientific name, Corydoras axelrodi. However, it is also known by several other common names, including Axelrod’s Corydoras, Pink Cory, and Red Corydoras. These names are derived from its vibrant pink coloration and the significant contributions of Dr. Herbert R. Axelrod to the aquarium fish industry.

The popularity of Pink Corydoras in the aquarium trade has led to its widespread recognition and the use of various common names. These names not only reflect its physical appearance but also pay homage to the individuals and institutions that have played a crucial role in its discovery and popularity.

In conclusion, Pink Corydoras, scientifically known as Corydoras axelrodi, belongs to the family Callichthyidae and the genus Corydoras. Named after Dr. Herbert R. Axelrod, this species is native to the upper Orinoco River basin in Venezuela and Colombia. It is commonly referred to as Axelrod’s Corydoras, Pink Cory, or Red Corydoras, highlighting its striking pink coloration and the contributions of Dr. Axelrod to the aquarium fish trade. Understanding the taxonomy and common names associated with Pink Corydoras enhances our appreciation for this captivating species and its significance in the aquarium hobbyist community.

Physical Characteristics

The general appearance and body shape of Pink Corydoras are quite distinctive. These small freshwater fish have a compact and streamlined body, typical of the Corydoras genus. They have a flattened ventral region and a rounded snout, which gives them a somewhat chubby appearance. The body is covered in bony plates called scutes, providing protection against potential predators.

The most remarkable feature of Pink Corydoras is their stunning pink coloration. Unlike other species in the Corydoras genus, which typically display shades of brown or gray, Pink Corydoras exhibit a vibrant pink hue that is truly eye-catching. This unique coloration is believed to be a result of selective breeding in captivity, as wild Corydoras axelrodi usually have a more subdued coloration.

The pink coloration of Pink Corydoras is primarily concentrated on their body, with variations in intensity and distribution. Some individuals may have a uniform pink coloration, while others may display a pattern of pink spots or stripes. The intensity of the pink color can also vary, ranging from pale pink to a deeper, almost reddish shade.

In addition to the pink coloration, there can be variations in color patterns within the Pink Corydoras species. Some individuals may exhibit a more mottled or speckled appearance, with patches of pink intermingled with other colors, such as brown or gray. These variations in color patterns add to the visual appeal and uniqueness of each Pink Corydoras specimen.

It is important to note that the pink coloration of Pink Corydoras is not permanent and can be influenced by various factors, including stress, diet, and water conditions. The color intensity may fade or change over time, especially if the fish is not provided with optimal care and conditions. Therefore, maintaining suitable water parameters and providing a balanced diet is crucial to preserve the vibrant pink coloration of Pink Corydoras.

To better understand the genetic basis of the pink coloration in Pink Corydoras, researchers have conducted studies to identify the specific genes responsible for this unique trait. These studies have revealed that the pink coloration is associated with certain genetic mutations that affect the production and distribution of pigments in the fish’s skin cells.

In conclusion, Pink Corydoras exhibit a distinct appearance and body shape, with their notable pink coloration being the most striking feature. The variations in color patterns within the species further contribute to their visual appeal. Understanding the factors that influence the pink coloration and preserving optimal conditions are essential for maintaining the vibrant and captivating appearance of Pink Corydoras in aquariums.

Natural Habitat and Distribution

The natural habitat of Pink Corydoras, scientifically known as Corydoras axelrodi, primarily consists of rivers and streams in South America. These vibrant and captivating fish are native to the Amazon River basin, specifically found in the countries of Brazil, Colombia, and Venezuela. Within this region, Pink Corydoras inhabit various tributaries and smaller water bodies, including the Rio Negro and Orinoco River systems.

The geographical distribution of Pink Corydoras is predominantly centered around the Orinoco River basin, which spans across Venezuela and parts of Colombia. This expansive river system provides an ideal environment for these fish to thrive due to its diverse ecosystems and abundant food sources. Additionally, Pink Corydoras can also be found in the Rio Negro basin, a major tributary of the Amazon River, further extending their distribution range within the Amazon rainforest.

Pink Corydoras have adapted to specific environmental conditions in their natural habitat. These fish prefer slow-moving or still waters with sandy or muddy substrates, where they can easily scavenge for food and sift through the substrate for small invertebrates. The water in their native habitat tends to be soft and slightly acidic, with temperatures ranging from 75-82°F (24-28°C). It is important to note that Pink Corydoras are highly adaptable and can tolerate a range of water conditions, but they thrive best in conditions that mimic their natural habitat.

In their wild environment, Pink Corydoras are often found in densely vegetated areas, where they can seek shelter and feel secure. The presence of aquatic plants, fallen leaves, and submerged roots provide hiding spots and mimic the natural environment that these fish are accustomed to. These elements also contribute to the overall water quality by providing natural filtration and maintaining stable water parameters.

Furthermore, the Amazon rainforest is known for its rich biodiversity, and Pink Corydoras coexist with various other fish species, such as tetras, catfish, and dwarf cichlids. This interdependence and ecological balance within their natural habitat highlight the importance of maintaining a harmonious community in aquarium setups.

In conclusion, understanding the natural habitat and distribution of Pink Corydoras is crucial for providing optimal care in captivity. By replicating their preferred environmental conditions, such as soft and slightly acidic water, sandy substrates, and the presence of vegetation, aquarists can ensure the well-being and longevity of these captivating fish. Additionally, considering the geographical distribution and coexistence with other fish species in the wild can guide aquarists in creating a compatible and thriving community aquarium.

Behavior and Social Structure

Typical Behavior of Pink Corydoras in Aquariums

Pink Corydoras, scientifically known as Corydoras axelrodi, exhibit fascinating behavior in aquariums. They are generally peaceful and active fish, constantly exploring their surroundings. These fish are primarily bottom-dwellers, spending the majority of their time scavenging for food and sifting through the substrate.

One of the most endearing behaviors of Pink Corydoras is their habit of “popping” up to the water’s surface to take gulps of air. This behavior is not a sign of distress but rather an adaptation to the low oxygen levels typically found in their natural habitat. It is essential to provide these fish with access to the water’s surface to perform this behavior comfortably.

Schooling Nature and Social Interactions

Pink Corydoras are highly social fish and thrive in groups. They exhibit a strong schooling instinct, preferring to be kept in groups of at least six individuals. When kept in smaller numbers, they may become stressed and exhibit less natural behavior.

In a school, Pink Corydoras engage in synchronized movements, creating a stunning display of unity. They swim in close proximity to one another, forming a cohesive unit that provides them with a sense of security. This schooling behavior also serves as a defense mechanism against predators in the wild.

Furthermore, Pink Corydoras show a remarkable level of social interaction within their school. They engage in playful chasing and mimicry, often mirroring the movements of their companions. This behavior reinforces their bond and strengthens the overall cohesion of the group.

Unique Behaviors and Habits of Pink Corydoras

One unique behavior of Pink Corydoras is their ability to produce audible sounds. These sounds, often described as clicking or chirping noises, are produced by the fish rubbing their pectoral spines together. It is believed that this behavior serves as a form of communication within the group or during courtship rituals.

Another interesting behavior exhibited by Pink Corydoras is their ability to swim upside down. While this behavior may initially seem concerning, it is a natural and normal behavior for these fish. They do this to access food particles that have settled on the water’s surface or to explore their environment from a different perspective.

Additionally, Pink Corydoras have a fascinating habit of “playing dead” when they feel threatened. They will lie motionless on their sides, mimicking a deceased fish. This behavior is believed to be a defense mechanism to deter potential predators. Once the perceived threat has passed, they quickly resume their normal activity.

In conclusion, Pink Corydoras display a range of captivating behaviors in aquariums. Their schooling nature, synchronized movements, and social interactions make them a joy to observe. Their ability to produce sounds, swim upside down, and play dead adds further intrigue to their already fascinating behavior repertoire. By understanding and appreciating these behaviors, aquarists can provide a more enriching and fulfilling environment for their Pink Corydoras.

Feeding Habits and Diet

Dietary Requirements of Pink Corydoras

Pink Corydoras, like other Corydoras species, are omnivorous, meaning they consume both plant matter and small invertebrates. In their natural habitat, they primarily feed on small crustaceans, worms, insect larvae, and plant material. It is important to replicate their natural diet as closely as possible in captivity to ensure their optimal health and well-being.

Suitable Food Options for Pink Corydoras

When it comes to feeding Pink Corydoras in an aquarium setting, a varied diet is key. High-quality commercial fish foods such as flakes and pellets specifically formulated for bottom-dwelling fish can serve as a staple diet. These foods should be rich in protein and contain essential nutrients like vitamins and minerals.

In addition to commercial foods, Pink Corydoras greatly benefit from the inclusion of live or frozen foods in their diet. Offerings such as bloodworms, brine shrimp, daphnia, and blackworms are excellent choices. These live or frozen foods mimic the natural prey items found in their native habitat, providing them with essential nutrients and stimulating their natural feeding behaviors.

Feeding Behaviors and Preferences of Pink Corydoras

Pink Corydoras are known for their bottom-dwelling nature and have a unique feeding behavior. They have specialized barbels around their mouths that help them locate food particles on the substrate. These barbels are highly sensitive and allow them to sift through sand or gravel in search of food.

It is important to note that Pink Corydoras are primarily nocturnal feeders. They are most active during the night, so it is recommended to feed them in the evening or use automatic feeders to ensure they receive proper nutrition. Feeding them after the lights have been dimmed in the aquarium will encourage their natural feeding behaviors.

Furthermore, Pink Corydoras are social feeders and tend to feed in groups. They are more likely to eat when they see other members of their species or other bottom-dwelling fish feeding. Therefore, it is beneficial to keep them in groups of at least six individuals to promote healthy feeding behaviors.

To ensure that Pink Corydoras receive adequate nutrition, it is essential to monitor their feeding habits closely. Uneaten food should be promptly removed from the aquarium to maintain water quality and prevent the accumulation of waste.

In conclusion, Pink Corydoras have specific dietary requirements that should be met to promote their overall health and vitality. Providing a varied diet consisting of high-quality commercial foods, supplemented with live or frozen foods, will ensure they receive the necessary nutrients. Understanding their feeding behaviors and preferences, such as their nocturnal nature and social feeding habits, will contribute to their well-being in a captive environment. By offering a well-balanced diet and promoting natural feeding behaviors, aquarists can ensure the long-term health and enjoyment of Pink Corydoras in their aquariums.

Breeding and Reproduction

Reproductive Behavior and Spawning Process

Pink Corydoras, like many other species of Corydoras, exhibit interesting reproductive behavior. They engage in a unique courtship ritual prior to spawning. During this ritual, the male and female fish swim in close proximity, with the male often playfully chasing the female. This behavior serves as a way for the male to demonstrate his fitness and readiness to reproduce.

Once the female is ready to spawn, she will lay her eggs on a flat surface, such as a broad leaf or the aquarium glass. The male then fertilizes the eggs by releasing his milt, which contains sperm, over the eggs. This process usually occurs during the early morning hours and can last for several hours.

Conditions for Successful Breeding in Captivity

Breeding Pink Corydoras in captivity can be a rewarding experience for aquarium enthusiasts. However, creating the right conditions is crucial for successful breeding. Here are some key factors to consider:

  1. Water Parameters: Pink Corydoras prefer slightly acidic to neutral water conditions, with a pH range of 6.5 to 7.5. The temperature should be maintained between 75°F and 80°F (24°C to 27°C). It is important to ensure stable water parameters, as sudden fluctuations can stress the fish and hinder the breeding process.
  2. Spawning Surface: Providing suitable spawning surfaces is essential for Pink Corydoras to lay their eggs. Broad-leaved plants, such as Amazon swords or anubias, can serve as ideal surfaces. Additionally, a smooth substrate, such as fine gravel or sand, should be used to prevent damage to the delicate eggs.
  3. Adequate Space: Pink Corydoras require sufficient space to engage in their courtship rituals and to lay their eggs. A spacious tank with a minimum size of 20 gallons is recommended for breeding purposes. This allows for ample swimming and spawning areas, reducing the likelihood of aggression between fish.
  4. High-Quality Diet: To ensure optimal breeding conditions, it is important to provide a varied and nutritious diet to Pink Corydoras. A diet rich in high-quality protein, such as live or frozen foods like bloodworms or brine shrimp, can enhance their reproductive health and increase the chances of successful breeding.

Challenges and Considerations in Breeding Pink Corydoras

Breeding Pink Corydoras can present some challenges, and it is important to be aware of these considerations:

  1. Compatibility: While Pink Corydoras are generally peaceful fish, it is crucial to ensure compatibility between breeding pairs. Aggressive or dominant fish may disrupt the breeding process or harm the eggs. It is recommended to keep a ratio of one male to two or more females to distribute any potential aggression.
  2. Water Quality: Maintaining excellent water quality is crucial for the health and successful breeding of Pink Corydoras. Regular water changes, adequate filtration, and monitoring of water parameters are essential. Poor water quality can lead to stress, disease, or even the failure of eggs to hatch.
  3. Patience and Observation: Breeding Pink Corydoras requires patience and keen observation. The courtship and spawning process may take time, and it is important not to rush or disturb the fish during this period. Careful monitoring of the tank and the behavior of the fish is necessary to ensure the best chance of successful breeding.

In conclusion, breeding Pink Corydoras can be a fascinating and rewarding experience for aquarium enthusiasts. By understanding their reproductive behavior, providing suitable conditions, and addressing potential challenges, aquarists can increase the likelihood of successful breeding. Remember to prioritize the well-being of the fish and maintain optimal water quality throughout the process. With proper care and attention, you can contribute to the conservation of this beautiful species while enjoying the wonders of their breeding behavior in your own aquarium.

Aquarium Care and Maintenance

Setting up an aquarium suitable for Pink Corydoras

Creating an ideal habitat for Pink Corydoras requires careful consideration of various factors to ensure their well-being and thriving. Here are some guidelines to follow:

  1. Tank SizePink Corydoras are relatively small fish, reaching an average length of 2-3 inches (5-7.5 cm). To provide ample swimming space and accommodate a small group of these social creatures, it is recommended to have a tank with a minimum capacity of 20 gallons (75 liters). A larger tank is always better as it allows for more stable water conditions and reduces the risk of overcrowding.
  2. Filtration SystemProper filtration is crucial for maintaining a healthy environment for Pink Corydoras. Since they are sensitive to poor water quality, it is essential to have a high-quality filtration system that can remove waste and toxins. It is recommended to use a combination of mechanical, biological, and chemical filtration. Consider using a sponge filter or a canister filter with a gentle flow to prevent the fish from being stressed by strong currents.
  3. Water ParametersPink Corydoras thrive in slightly acidic to neutral water conditions. Aim for a pH level between 6.5 and 7.5, with a water temperature ranging from 72°F to 78°F (22°C to 26°C). Regularly monitoring and maintaining these parameters is important for the well-being of your fish. Using a reliable water testing kit will help you keep track of ammonia, nitrite, and nitrate levels, which should ideally be kept at zero.

Compatibility with other fish species

When considering tankmates for Pink Corydoras in a community aquarium, it is essential to choose species that are compatible with their peaceful nature. Here are some suitable companions:

  1. Peaceful Community FishPink Corydoras are peaceful and non-aggressive, making them ideal tankmates for other peaceful community fish. Species such as tetras, guppies, mollies, and small rasboras can coexist harmoniously with Pink Corydoras.
  2. Avoid Aggressive or Nippy FishIt is important to avoid housing Pink Corydoras with aggressive or fin-nipping species as they can stress and harm these gentle fish. Aggressive cichlids, barbs, and larger predatory fish should be avoided to ensure the safety and well-being of your Pink Corydoras.
  3. Bottom-Dwelling SpeciesPink Corydoras are primarily bottom-dwelling fish, so it is advisable to select tankmates that occupy different areas of the aquarium. This reduces competition for food and territory. Consider adding peaceful bottom-dwelling species such as dwarf shrimp, small catfish, or loaches to create a diverse and balanced community.

Care requirements and considerations

Pink Corydoras have specific care requirements and considerations that should be taken into account to create an optimal environment for their well-being:

  1. Hiding Spots and PlantsPink Corydoras are naturally shy and appreciate hiding spots in the aquarium. Provide them with caves, driftwood, or dense vegetation like live plants to create secure hiding places. This will help reduce stress and provide a sense of security for these fish.
  2. SubstrateA soft substrate, such as fine sand or smooth gravel, is recommended for Pink Corydoras. Their delicate barbels, which resemble whiskers, are sensitive and can be easily damaged by rough substrates. Avoid using sharp or coarse gravel to prevent injury.
  3. LightingPink Corydoras do not have any specific lighting requirements, but it is important to provide a natural day-night cycle. A regular lighting schedule of 8-10 hours of light per day is sufficient. Avoid intense or direct lighting as it can cause stress and discomfort for these fish.
  4. Water Quality and MaintenanceRegular water changes are crucial for maintaining optimal water quality. Aim for weekly water changes of 20-30% to remove accumulated waste and maintain stable water parameters. Use a siphon to clean the substrate and remove any debris. Avoid using chemical additives unless necessary, as Pink Corydoras are sensitive to certain medications and water treatments.

In conclusion, providing the best care and suitable conditions for Pink Corydoras is essential for their overall health and well-being. By following the guidelines outlined above, you can create a thriving and harmonious aquarium environment for these captivating fish. Remember to monitor water parameters regularly, choose compatible tankmates, and provide adequate hiding spots and plants to ensure the happiness and longevity of your Pink Corydoras.

Common Health Issues and Diseases

Pink Corydoras, like any other fish species, are susceptible to certain health issues and diseases. It is important for aquarium owners to be aware of these common ailments and take preventive measures to ensure the well-being of their Pink Corydoras.

Fin Rot

One common health issue that Pink Corydoras may encounter is fin rot. Fin rot is a bacterial infection that affects the fins and can lead to deterioration and even loss of the affected fins. It is often caused by poor water quality, stress, or injuries. Symptoms of fin rot include frayed or discolored fins, inflammation, and lethargy. If left untreated, fin rot can spread to the body of the fish and cause more serious health problems.

Ich (White Spot Disease)

Another common ailment that Pink Corydoras may experience is ich, also known as white spot disease. Ich is caused by a parasitic protozoan called Ichthyophthirius multifiliis and is characterized by the appearance of small white spots on the fish’s body and fins. Infected fish may exhibit symptoms such as scratching against objects, rapid breathing, and loss of appetite. If not treated promptly, ich can weaken the fish’s immune system and make it more susceptible to other diseases.

Prevention and Care

To prevent these health issues and maintain the overall health of Pink Corydoras, it is crucial to provide proper care and create suitable conditions in the aquarium. Here are some important steps to follow:

  1. Regular water changes: Perform weekly water changes of around 25% to 50% of the tank volume to remove excess waste, toxins, and bacteria that can contribute to the development of diseases.
  2. Monitor water parameters: Test the water regularly using reliable test kits to ensure pH levels between 6.5 and 7.5, temperature between 72°F and 78°F (22°C to 26°C), and zero presence of ammonia and nitrite.
  3. Provide a well-balanced diet: Offer a varied diet consisting of high-quality flakes, pellets, and live/frozen foods such as brine shrimp or bloodworms to provide essential nutrients and boost the immune system.


In the unfortunate event that Pink Corydoras do develop health issues, prompt treatment is necessary to prevent further complications. Follow these steps:

  1. Use appropriate medication: Use medication specifically formulated to treat bacterial infections or parasites, such as those for fin rot or ich. Follow the instructions provided by the manufacturer.
  2. Consult a professional: If needed, consult with a veterinarian or experienced fish keeper for guidance on treatment options.
  3. Consider quarantine: In some cases, quarantine may be necessary to prevent the spread of diseases to other fish in the aquarium.

In conclusion, being aware of common health issues and diseases that Pink Corydoras may encounter is essential for their proper care and well-being. By taking preventive measures such as regular water changes, monitoring water parameters, providing a balanced diet, and promptly treating any ailments that may arise, aquarium owners can ensure that their Pink Corydoras thrive in a healthy and disease-free environment. Responsible ownership and proactive care are key to maintaining the vibrant beauty and longevity of these fascinating fish.


Pink Corydoras, also known as Corydoras axelrodi, are a fascinating species of fish commonly found in South America. Throughout this comprehensive guide, we have explored various aspects of Pink Corydoras, including their taxonomy, physical characteristics, natural habitat, behavior, feeding habits, breeding, aquarium care, common health issues, conservation status, and more. It is crucial to emphasize the importance of providing proper care and suitable conditions for Pink Corydoras in captivity.

One of the key takeaways from this article is the significance of creating an environment that mimics their natural habitat. Pink Corydoras thrive in rivers and streams with clean water, so maintaining high water quality in their aquariums is essential. Regular water changes, appropriate filtration systems, and monitoring water parameters such as temperature, pH, and ammonia levels are vital for their well-being.

Furthermore, Pink Corydoras are social fish that prefer to live in groups, known as schools. Providing them with suitable tank mates and enough space to swim and explore is crucial. Creating hiding spots and incorporating live plants in the aquarium can help replicate their natural environment and provide them with a sense of security.

When it comes to feeding, Pink Corydoras are omnivorous and have specific dietary requirements. A balanced diet consisting of high-quality flakes, pellets, and occasional live or frozen foods such as bloodworms or brine shrimp is essential for their overall health and vitality. It is important to note that overfeeding should be avoided, as it can lead to health issues such as obesity and poor water quality.

Breeding Pink Corydoras in captivity can be a rewarding experience, but it requires specific conditions and careful attention. Providing them with appropriate breeding caves or flat surfaces for spawning, maintaining optimal water parameters, and ensuring a well-balanced diet are crucial for successful reproduction. However, it is important to note that breeding can be challenging and may require additional research and expertise.

In terms of their conservation status, Pink Corydoras face threats such as habitat destruction and overfishing. Supporting conservation efforts and initiatives aimed at protecting this species and their natural habitats is crucial. Responsible ownership and education about Pink Corydoras can contribute to their conservation by promoting sustainable practices and minimizing the impact on their wild populations.

In conclusion, Pink Corydoras are a captivating species that have gained popularity in the aquarium trade due to their unique pink coloration and fascinating behavior. Providing proper care and suitable conditions for Pink Corydoras in captivity is of utmost importance to ensure their well-being and longevity. By understanding their natural habitat, behavior, feeding habits, and breeding requirements, aquarium enthusiasts can create an environment that closely resembles their native rivers and streams. Encouraging further research and responsible ownership of Pink Corydoras is essential to promote their conservation and the preservation of their natural habitats for future generations to appreciate and enjoy.