What Is The Difference Between Altum And Scalare Angelfish
The primary difference is that Altum angelfish are significantly larger with a distinct notched snout, while Scalare angelfish are smaller, more common, and much easier for hobbyists to keep and breed in home aquariums.
For many of us, the angelfish is the ultimate centerpiece of a freshwater aquarium.
I still remember the first time I saw a true Altum; its sheer height and regal posture were unlike anything I had seen in a standard pet store.
If you are trying to understand what is the difference between altum and scalare angelfish, you are likely looking to elevate your fish-keeping game.
Both belong to the genus Pterophyllum, but they represent very different challenges and aesthetic profiles for the dedicated aquarist.
By understanding these nuances, you can ensure you provide the right environment for whichever “King” you choose to bring home.
Let’s dive into the specifics of these two remarkable species and how you can tell them apart at a glance.
The Visual Identity: Spotting the Physical Differences
At first glance, many beginners might think all angelfish look the same.
However, once you know what to look for, the physical markers between Pterophyllum altum and Pterophyllum scalare are quite obvious.
The most striking difference is the overall size and the “profile” of the fish’s head.
The Famous Pre-Orbital Notch
The easiest way to answer what is the difference between altum and scalare angelfish visually is to look at the nose.
Altum angelfish possess a very distinct “indentation” or “notch” just above their snout.
In scientific circles, this is often referred to as a supraorbital indentation or a pre-orbital notch.
This gives the Altum a “turned-up” nose appearance that is much more pronounced than the smoother, more rounded profile of the Scalare.
Vertical Stature and Fin Length
Altums are the giants of the angelfish world, often reaching heights of 12 to 15 inches including their fins.
Their bodies are more compressed and taller relative to their length than the Scalare.
Scalare angelfish are generally smaller, usually topping out around 6 to 8 inches in height.
While Scalares are still impressive, they lack the extreme verticality that makes a school of Altums so breathtaking.
Pro Tip: If you are planning to keep Altums, you must prioritize tank height over length. I have found that a minimum of 24 to 30 inches in height is necessary to prevent their long, delicate fins from touching the substrate.
Geographic Origins and Natural Habitats
Understanding where these fish come from is crucial for anyone trying to replicate their natural environment effectively.
While both species are South American cichlids, they occupy different river systems with distinct water chemistry.
The Realm of the Altum: The Orinoco River Basin
True Altums are primarily found in the Orinoco River basin and the upper Rio Negro.
These areas are famous for their blackwater biotope conditions.
The water here is stained the color of dark tea due to the high concentration of humic substances leaching from decaying leaf litter.
This environment is extremely acidic and almost entirely devoid of minerals, which makes the Altum a much more sensitive fish in captivity.
The Versatile Scalare: A Wider Amazonian Range
Pterophyllum scalare has a much broader distribution across the Amazon River basin.
They are found in Peru, Brazil, and Colombia, inhabiting a variety of water types from clear water to whitewater.
Because they have evolved across such a wide range of conditions, they are naturally more adaptable to different water parameters in the home aquarium.
Most Scalares you find in shops today are tank-bred, making them even more resilient than their wild ancestors.
When people ask what is the difference between altum and scalare angelfish, they are often surprised to learn how different their water needs are.
Maintaining the proper water parameters is the difference between a thriving fish and a tragedy.
Specific Conductance and Hardness
Altums require very specific water conditions to survive long-term.
In their native habitats, the specific conductance is incredibly low, meaning there are very few dissolved solids in the water.
They thrive in water with almost zero carbonate hardness (KH) and a very low pH, sometimes as low as 4.0 or 5.0.
In my experience, attempting to keep Altums in “liquid rock” (hard tap water) usually leads to a weakened immune system and a shortened lifespan.
The Adaptability of the Scalare
Scalares are far more forgiving when it comes to water chemistry.
While they still prefer slightly acidic to neutral water, they can easily adapt to a pH of 7.5 or even slightly higher.
They can also handle a moderate amount of mineral content, which makes them the perfect choice for the average hobbyist who doesn’t want to mess with RO/DI systems and peat filtration.
| Feature | Altum Angelfish (P. altum) | Scalare Angelfish (P. scalare) |
|---|---|---|
| Common Name | Deep Angelfish / Orinoco Altum | Common Angelfish |
| Max Height | Up to 15 inches | 6 to 10 inches |
| Snout Shape | Distinct notched (pre-orbital notch) | Straight or slightly curved snout |
| Water pH | 4.5 – 6.0 (Very Acidic) | 6.0 – 7.5 (Flexible) |
| Ease of Care | Difficult (Expert) | Easy to Moderate (Beginner) |
| Breeding | Extremely Rare/Hard in captivity | Common and relatively easy |
Both species are cichlids, which means they have personality, intelligence, and a bit of an attitude.
However, the way they interact with their environment and tank mates can vary.
Temperament Differences
In my observations, Altums tend to be more “skittish” than Scalares.
Because many Altums in the trade are wild-caught, they retain their natural instincts to hide from shadows or sudden movements.
Scalares, having been domesticated for decades, are much more likely to “beg” for food at the front of the glass.
They are generally more outgoing, though they can become quite territorial during spawning.
Compatibility with Other Fish
When considering what is the difference between altum and scalare angelfish regarding tank mates, size is the biggest factor.
Altums are large enough to make a meal out of even medium-sized tetras.
I always recommend larger, peaceful tank mates for Altums, such as Rummy Nose Tetras or larger Corydoras.
Scalares are also predatory, but because they are smaller, they can often be kept with a wider variety of community fish.
Common Mistake: Do not buy “Altum” angelfish from a source you don’t trust. Many sellers mislabel “Peruvian Altums,” which are actually a variety of Pterophyllum scalare, not the true Pterophyllum altum. If the price is too good to be true, it’s probably a Scalare!
Breeding: The Ultimate Challenge
For many hobbyists, the dream is to breed their fish.
If this is your goal, the choice between these two species is very clear.
Breeding the Scalare
Scalare angelfish are the bread and butter of the aquarium breeding world.
They are excellent parents and will readily lay eggs on broad-leafed plants, slate, or even the aquarium glass.
With a little patience and good nutrition, almost any intermediate hobbyist can successfully raise a batch of Scalare fry.
The Mystery of Altum Spawning
Breeding true Altums is considered one of the “Holy Grails” of the freshwater hobby.
It happens so rarely in captivity that it often makes national news in the fish-keeping community.
The exact triggers—ranging from atmospheric pressure changes to precise shifts in specific conductance—are hard to replicate.
If you are a beginner, I strongly suggest starting with Scalares to learn the ropes of cichlid behavior.
Coloration and Variations
One major point in the what is the difference between altum and scalare angelfish debate is the variety of colors available.
Natural Beauty vs. Selective Breeding
Altums are almost always found in their “wild type” coloration.
This consists of a silver-green body with four primary dark vertical bars.
They often have small red spots or a reddish tint on their backs, which is a beautiful trait of the Orinoco populations.
Scalares, on the other hand, come in a dizzying array of colors and fin types.
Through decades of selective breeding, we now have Marble, Gold, Koi, Black, and even “Blue” Scalares.
If you want a specific color palette for your aquascape, Scalares are the way to go.
Setting Up the Perfect Aquarium
Whether you choose the towering Altum or the hardy Scalare, your setup needs to reflect their needs.
Filtration and Flow
Both species come from relatively slow-moving waters.
They have large, sail-like fins that act like “parachutes” in high current, which can stress them out.
I prefer using large sponge filters or canister filters with a spray bar to distribute the flow evenly.
For Altums, keeping the water pristine is non-negotiable.
They are highly susceptible to “Hole in the Head” disease if nitrates are allowed to creep up.
Decor and Plants
I always recommend a heavily planted tank for Scalares.
They love weaving through Amazon Swords and Valisneria.
For Altums, a blackwater biotope setup with large pieces of driftwood and dried Catappa leaves is ideal.
The tannins released from the leaves provide those essential humic substances that help mimic their natural home.
Frequently Asked Questions (FAQ)
Can Altum and Scalare angelfish live together?
Technically, yes, they can coexist if the tank is large enough. However, it is not recommended. The Altum’s need for very soft, acidic water is much stricter than the Scalare’s, making it difficult to find a middle ground where both thrive.
Why are Altum angelfish so much more expensive?
Altums are often wild-caught and must be imported from remote areas of the Orinoco River basin. The cost of shipping, combined with their sensitivity and the difficulty of breeding them in captivity, keeps their price point high.
How can I tell if my “Altum” is a real Altum?
Look for the supraorbital indentation (the notch on the nose) and the count of the vertical bars. True Altums also have a much taller, thinner body shape. If the fish is very colorful or has “lace” fins, it is almost certainly a Scalare variety.
Do Altums need a heater?
Yes, absolutely. Both species are tropical, but Altums generally prefer slightly warmer water, often between 82°F and 86°F. Scalares are comfortable in a slightly wider range of 76°F to 82°F.
What should I feed them?
In the wild, both are opportunistic carnivores. In my tanks, I provide a mix of high-quality flakes, frozen bloodworms, and live brine shrimp. Altums can be finicky at first, so live foods are often necessary to get them eating.
Conclusion
Understanding what is the difference between altum and scalare angelfish is the first step toward becoming a master of these “Kings of the Aquarium.”
If you are a beginner or looking for a colorful, hardy centerpiece for your community tank, the Scalare is an unbeatable choice.
Their adaptability and ease of breeding make them a joy to keep.
However, if you are an experienced aquarist looking for the ultimate challenge, the Altum angelfish offers a level of majesty that is hard to match.
The commitment to maintaining a blackwater biotope and perfect water chemistry is high, but the reward of seeing a school of 15-inch giants is well worth the effort.
Whichever species you choose, remember that consistency is the key to success.
Keep your water clean, your fish well-fed, and your eyes on those beautiful fins!