Angelfish Size: How Big Do They Get?

Angelfish is a term often used to describe several species of fish, but typically refers to the freshwater Pterophyllum species. They are popular in the aquarium hobby for their striking appearance. These tropical fish originate from the Amazon River basin in South America. Being a cichlid, their nature is more aggressive and territorial than your average community fish.

angelfish size

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What is the Average Size of Angelfish?

To answer your question directly, the average size of Angelfish can vary depending on the species. This exotic fish species boasts several variants, each having its unique growth potential and size range.

  • For instance, the P. scalare angelfish, a very common variation, seldom exceeds the body length of 6 inches or 15 cm. Including their beautifully arching fins, they can reach a height of 8 inches or 20 cm, offering a delightful visual spectacle.
  • On the other hand, the slightly bigger Altum angelfish or P. altum can outgrow their P. scalare counterparts. Attaining lengths up to 7 inches or 18 cm, and an impressive height range of 10-13 inches or 25-33 cm, they unmistakably express the growth potential in Angelfishes.

These sizes are, of course, under optimal living conditions and proper care. The actual size your Angelfish may reach can be influenced by several factors, including diet, environment, and genetics. It’s important to remember that these are only averages, and individual fishes can exceed these lengths.

Just like humans, each Angelfish has its own growth rate and developmental milestones, making them unique and fascinating pets for aquarists of any experience level. This range of sizes among the diverse Angelfish species makes them suitable for different sizes of home aquariums, contributing to their popularity among fish enthusiasts.

What is the Growth Rate of Angelfish?

The growth rate of Angelfish varies depending on several key factors. But generally, it tends to be quite rapid within their first year.

  • Under ideal conditions, the average Angelfish typically reach half its adult size in approximately 6 months.
  • By 12 months, they should be close, if not already at, full adult size.
  • Altum Angelfish, one of the larger species, also exhibit a swift growth rate, reaching 7 inches (18 cm) long and up to 13 inches (33 cm) high in just over a year.

However, it’s essential to note that these numbers are not universal. Environmental conditions, diet, and genetics play a significant part in their growth rates.

If you’re raising angelfish in an aquarium, there are steps you can take to encourage optimum growth:

  • Ensure the tank is at least 20 gallons, larger for Altum species.
  • Feed a diet rich in protein, including live or freeze-dried foods.
  • Keep water conditions optimal, maintaining a pH level of 6.5 – 7.0.

By focusing on these factors, your Angelfish should be able to reach their full size within the span of a year. Remember, rapid growth isn’t necessarily best. Proper, steady development ensures your Angelfish will live a healthy, full life.

Are There Size Differences Between Male and Female Angelfish?

In the vast world of angelfish, size differences between the sexes are not significantly noticeable. While there may be a slight disparity in size, this is not a reliable method to differentiate males from females.

  • Males and females share a similar range, generally reaching lengths of 6-7 inches and heights of up to 8-13 inches.
  • With a variance in size so small, it’s often challenging to notice a difference without careful observation.

The males, in some species, may have a more prominent dorsal hump or exhibit more vibrant coloration during the breeding season. Still, these are quite subjective and can’t be taken as a surefire indicator.

Why is this the case?

Well, in angelfish, sexual dimorphism (visible differences between sexes) is less pronounced compared to other fish species. Thus, size remains an ineffective method of distinguishing between male and female angelfish.

When considering fish tank communities, it’s helpful to remember it’s not just about size. Behavior, compatibility, and environment also hold equal importance. So, whether male or female, both contribute equally to your aquarium’s liveliness, shedding light on the well-known fact that size doesn’t always matter.

When do Angelfish Reach Full Size?

It’s crucial to know the right time when your angelfish reaches its full size. This information can aid you in offering them the correct care needed at different growth stages.

Angelfish generally take around 10 to 12 months to attain their adult size. However, keep in mind that this largely depends on their:

  • Diet: The better the feed, the quicker they grow.
  • Tank conditions: Comfortable and clean conditions promote quick growth.
  • Genetics: Certain strains naturally grow faster.

On average, a common P. scalare angelfish, for instance, can reach a length of up to 6 inches (15 cm). However, an Altum angelfish (P. altum) can grow up to 7 inches in length and up to 10-13 inches high. Hence, take into account that the growth pattern can vary based on species.

In the first two weeks after hatching, their size is barely about 0.25 inches (0.63 cm). Notably, they grow quickly within the first five months, jumping to about 3 inches (7.6 cm) in size. This phase demands extra care and an abundance of quality feed to accommodate their rapid growth.

Past this initial period, their growth rate slows down considerably, and they usually hit the full size at about their first year mark. This is a gradual process that takes time and patience.

What Factors Influence the Size of Angelfish?

There are several factors that influence the size of angelfish. As with any living organism, genetics plays a fundamental role. Some angelfish species are simply larger than others; P. altum angelfish can reach lengths of 7 inches (18 cm), whereas P. scalare angelfish can only grow up to 6 inches (15 cm).

However, it’s not all about genetics. The environment an angelfish is in can significantly influence their size. This encompasses several aspects:

  • Tank Size: A larger tank can support a larger angelfish. Simply put, angelfish develop to fit their habitat.
  • Water Quality: Good water quality can promote growth, since a clean and balanced environment keeps the fish healthy.
  • Temperature: Angelfish grow faster in warmer water, but remember, too warm can also be detrimental.

Diet also plays a crucial role. Feeding your angelfish a varied, balanced diet can stimulate growth. Ensure their diet includes both meat-based and plant-based nutrients.

Lastly, stress levels can impact size. Angelfish that experience regular stress, whether from aggressive tank mates or drastic changes in their environment, may stunted growth.

How do Angelfish Compare in Size with Other Species?

When it comes to the size of aquatic species, the comparison can be quite fascinating. Angelfish are not the largest types but they surely can impress with their growth size.

  • Angelfish, whether P. scalare or P. altum, typically have remarkable heights. Growing to heights of up to 13 inches, they easily surpass many species in terms of vertical growth.

However, there are other species that push these limits even further. For instance:

  • The Oscar fish can grow up to 12-16 inches in length.
  • The Discus fish reach sizes close to their name, generally between 8 and 10 inches in diameter.

Aquarium enthusiasts may also compare angelfish to other common pet fish.

  • The goldfish, for instance, are relatively small, with an average length of 1- 2 inches in a home aquarium.
  • Betta fish on the other hand stay small and manageable, hardly growing above 2.5 inches.

Angelfish prove their stature in the aquarium by reaching more significant heights. They are taller than the betta or the guppy, and often wider – in terms of overall body span – than the discus or the goldfish. But remember, the true size of any fish depends on factors such as genetics, care, diet, and environment.


In essence, the size of an angelfish hinges on numerous factors, including type, gender, growth rate and environmental conditions. Understanding these factors equips you with the capability to provide a fitting habitat for your angelfish, fostering its healthy, full-size development. Do you have any thoughts or questions about angelfish sizes? We’d love to hear from you in the comments.

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