How Many Angelfish In a 30 Gallon Tank (120 Liters) To Keep? - "File:Pterophyllum scalare - Warsaw zoo.JPG" by Ewkaa is licensed under CC BY-SA 4.0.
How Many Angelfish In a 30 Gallon Tank (120 Liters) To Keep? - "File:Pterophyllum scalare - Warsaw zoo.JPG" by Ewkaa is licensed under CC BY-SA 4.0.


Setting up an aquarium can be an enriching experience, especially when it involves the graceful and mesmerizing angelfish. A common question among enthusiasts is, “How many angelfish in a 30 gallon tank (120 liters) can be housed comfortably?” This question is crucial for both the health of the angelfish and the overall balance of the aquarium environment. Understanding the spatial needs of angelfish and the dynamics of their behavior is key to creating a harmonious aquatic habitat. So, how many angelfish in a 30 gallon tank (120 liters) should you consider to ensure a thriving ecosystem? In this article, we delve into the specifics of tank setup, angelfish behavior, and the ideal number of angelfish for a 30 gallon setup (120 liter), ensuring a healthy and visually stunning aquarium.

About Angelfish

Angelfish, scientifically known as Pterophyllum scalare, are one of the most popular and recognizable species in the freshwater aquarium hobby. Their distinct appearance and fascinating behaviors have endeared them to enthusiasts worldwide.


Angelfish are distinguished by their strikingly elegant bodies, which are laterally compressed and roughly triangular in shape. They typically grow to about 6 inches (15 cm) in length, but their height, including the fins, can be as much as 8 inches (20 cm) or more, giving them a very imposing presence in an aquarium setting.

Their fins are particularly notable, with long and flowing dorsal and anal fins that extend above and below their bodies, enhancing their angelic appearance. The caudal (tail) fin is usually fan-shaped, adding to their gracefulness. Angelfish come in a variety of colors and patterns, ranging from silver with vertical black stripes to more elaborate colorations including gold, marble, koi, and even black.


Angelfish are known for their semi-aggressive temperament. They are generally peaceful with other fish but can become territorial, especially during breeding. They are cichlids, which means they have some complex social behaviors and can be aggressive towards smaller fish or those of a similar shape, which they may perceive as rivals.

In an aquarium setting, angelfish prefer well-planted environments with plenty of space to swim. They are quite sociable within their species and can often be seen swimming in loose groups, though they establish a pecking order within their community.

Angelfish are omnivores, feeding on a mix of plant matter and small invertebrates in the wild. In captivity, they readily accept a wide range of foods, including flakes, pellets, frozen, and live foods.

During breeding, angelfish behavior becomes even more fascinating. They are known to clean a flat surface (like a leaf or the aquarium glass) where the female will lay her eggs, and the male will fertilize them. They exhibit strong parental instincts, guarding their eggs and later, the fry, against potential threats. This protective behavior showcases their intelligence and complex social structure.

Overall, the appearance of Pterophyllum scalare is marked by their unique, triangular body shape and elegant, flowing fins, while their behavior blends peacefulness with territorial and complex breeding rituals. Their adaptability and striking looks make them a beloved choice for aquarium enthusiasts around the globe.

How Many Angelfish In a 30 Gallon Tank (120 Liters) Should You Have?

When determining how many angelfish in a 30-gallon tank (120 liters) is appropriate, it’s crucial to consider both the size of the fish and the environment you aim to provide. Angelfish require ample space to swim and thrive, not just because of their size but also due to their semi-aggressive nature and territorial behaviors, especially as they mature.

For Juvenile Angelfish

Young, smaller angelfish can be kept in a group more comfortably in a 30-gallon (120 liters) tank due to their smaller size. However, as they grow, they will require more space. Initially, you could start with a group of 4 to 5 juveniles, but be prepared to rehome some as they grow larger and their territorial behaviors become more pronounced. This approach allows for a social environment early on, which is beneficial for their development.

For Adult Angelfish

Adult angelfish can grow to be quite large. Given their size and space requirements for swimming and territories, a 30-gallon tank (120 liters) can become quite restrictive for multiple adult angelfish. For mature angelfish in a tank of this size, keeping a pair (2 individuals) is often recommended to prevent overcrowding and stress-related issues. This also allows for potential breeding, as a pair can form a bonded couple that might breed, requiring additional space for their breeding rituals and territorial behaviors.

General Considerations

  • Tank Setup: Ensure the tank is well-planted with areas for hiding and swimming. Angelfish appreciate vertical space due to their tall body shape, so a tank that is taller can also be beneficial.
  • Water Quality: Maintain high water quality with regular water changes and filtration, as overcrowding can lead to pollution and stress, harming the fish.
  • Social Dynamics: Monitor the social interactions among the fish. If aggression or stress signs are evident, adjustments in the number of fish or the tank setup may be necessary.
  • Future Planning: Be prepared to adjust the number of fish in the tank as they grow or if breeding occurs, to prevent overcrowding and ensure the well-being of all the inhabitants.

While you might start with a small group of juvenile angelfish in a 30-gallon tank (120 liters), it’s advisable to reduce the number to a single pair as they grow to adulthood to ensure their health and happiness. Always consider the long-term requirements of the fish and be prepared to make adjustments as needed.

How Many Angelfish In a 30 Gallon Tank (120 Liters) To Keep? - "File:Pterophyllum scalare - Warsaw zoo.JPG" by Ewkaa is licensed under CC BY-SA 4.0.
How Many Angelfish In a 30 Gallon Tank (120 Liters) To Keep? – “File:Pterophyllum scalare – Warsaw zoo.JPG” by Ewkaa is licensed under CC BY-SA 4.0.

Setting Up a 30 Gallon Tank for Angelfish

Setting up a 30-gallon tank for angelfish (120 liters) requires careful planning to meet their specific needs for space, water conditions, and environment. Angelfish are a popular choice for aquarium enthusiasts due to their elegant appearance and interesting behaviors, but they thrive best when their habitat is properly arranged. Here’s how to set up an ideal angelfish habitat in a 30-gallon tank (120 liter):

  • Size and Shape: A 30-gallon tank (120 liters) is a good starting point for keeping a pair of adult angelfish.
  • Efficient Filtration: Use a high-quality filter. Angelfish require clean water with stable conditions. A filter with adjustable flow can be a good choice, as strong currents can stress angelfish.
  • Stable Temperature: Maintain a water temperature between 76°F and 82°F (24°C to 28°C), which is ideal for angelfish. Use a reliable aquarium heater with a thermostat to keep the temperature stable.
  • Appropriate Lighting: Provide moderate lighting to support plant growth without encouraging excessive algae. Angelfish appreciate some shaded areas, so consider using floating plants or strategically placed decorations to create dim spots.
  • pH and Hardness: Keep the water slightly acidic to neutral (pH 6.5 to 7.0) and soft to moderately hard. Regularly test the water parameters using a water testing kit to ensure they remain within the suitable range.
  • Regular Water Changes: Perform weekly water changes of about 10-20% to maintain water quality, especially important in a densely stocked tank.
  • Substrate: Use a fine substrate, such as sand or small gravel, which can support plant growth and doesn’t injure the fish.
  • Plants and Decor: Create a densely planted environment with both tall and short plants, giving angelfish places to hide and explore. Include broad-leafed plants like Amazon swords for potential spawning sites. Driftwood, rocks, and caves can also provide shelter and contribute to the natural aesthetic.
  • Strategic Layout: Design the tank with open swimming areas and dense vegetation towards the back and sides. This arrangement mimics their natural habitat and supports their need for exploration and territorial behavior.
  • Avoid Overcrowding: While it’s tempting to add many decorative elements, ensure there’s enough open space for angelfish to swim freely.
  • Careful Selection: Choose peaceful fish that are not small enough to be considered prey by angelfish. Suitable tank mates include larger tetras, dwarf cichlids, and certain types of catfish. Avoid fin-nipping species and very small fish.
  • Gradual Introduction: When introducing angelfish to their new tank, acclimate them slowly to avoid shock from sudden changes in water parameters. This usually involves floating the bag in the tank to equalize temperature and then gradually mixing tank water into the bag.

By following these guidelines, you can create a thriving environment for your angelfish in a 30 gallon tank (120 liter), promoting their health, longevity, and natural behavior. Remember, the key to a successful angelfish tank is maintaining high water quality and providing a well-structured habitat that caters to their needs.


In conclusion, determining how many angelfish in a 30 gallon tank (120 liters) can be accommodated involves careful consideration of the angelfish’s size, behavior, and environmental needs. While a 30 gallon (120 liters) tank can initially support a small group of juvenile angelfish, it’s advisable to reduce the number to a pair as they mature to avoid overcrowding and stress. So, when pondering the question, “How many angelfish in a 30 gallon tank (120 liters) is ideal?” remember the importance of providing ample space for these elegant creatures to swim and exhibit their natural behaviors. By adhering to these guidelines, aquarists can ensure their angelfish lead healthy, happy lives in a beautifully maintained aquarium.