Angelfish are social but do not display schooling behavior. These elegant fish have a natural inclination to swim in loosely-organized groups or shoals with other angelfish (and with different fish genera and species), but they do not swim in a coordinated way like schooling fish.
When you see angelfish swimming in a group, it might appear that these are schooling fish. However, angelfish do not school. Angelfish swim in shoals, with each fish moving independently within the broader group of fish rather than in a synchronized pattern that defines schooling behavior.
Angelfish Do Not School But They Do Shoal
Angelfish (Pterophyllum scalare) are among the most attractive and charismatic tropical freshwater aquarium fish. These stunning fish have been a staple of freshwater aquariums for over a century. The popularity of angelfish is unsurprising when you become familiar with their beguiling beauty, graceful movements, and impressive intelligence.
Angelfish exhibit behavior that resembles schooling. Nevertheless, scientists and fish-keeping gurus do not categorize angels as schooling fish.
Instead, angelfish are shoaling fish. These regal aquatic creatures are social and generally congregate and swim groups called shoals but not schools.
Jeff Kubina [CC-BY-SA-2.0]Is There A Difference Between Schooling And Shoaling?
You might be wondering about the difference between schooling and shoaling.
These terms refer to the swimming behavior of fish aggregations adopt. Though distinct from each other, shoaling and schooling provide similar collective and individual benefits like:
- protection
- social interaction
- mating opportunities
- enhanced swimming efficiency
- improved food foraging and hunting outcomes
Let’s briefly examine what schooling and shoaling are and why these behaviors are related but distinct.
Schooling
When a group of fish swims in tightly-harmonized synchrony, they are schooling. Schooling fish coordinate the direction and speed of their movements with minute precision and explosive dynamism.
Schooling provides individual fish with advantages like protection against larger predators, increased access to food, and the potential for finding a mate for breeding.
The collective noun for these coordinated aggregations of fish is a school.
Groups of schooling fish (or schools) are usually composed of one species. However, some schools of fish consist of a predominant species and a smaller sub-group of separate species that typically have a similar appearance to the rest of the school.
Shoaling
In contrast, shoaling is a broad term to describe any group of fish moving together. Schoaling only becomes schooling if the fish are moving in unison.
Fish that shoal without schooling swim in a loose aggregation, with each fish making decisions about their movements while remaining within the broader boundaries of the group.
In a shoal (the collecting noun for a group of shoaling fish), individual fish interact with one another but choose their speed, directions, and feeding prerogatives, and they enter and leave the shoal as they please. Unlike schools, shoals consist of a diverse range of fish species.
How To Support Shoaling Behavior In Angelfish
So, we have established that angelfish are not schooling fish. We have also learned that they are social animals that prefer to live and swim in loosely-organized groups called shoals.
Fish-keepers should follow a few basic guidelines to encourage and support healthy shoaling behavior in angelfish.
Keep Multiple Angelfish
Keeping multiple angelfish in a tank is the first and most obvious way to create the conditions for the fish to shoal.
It is advisable to have at least five to six angelfish living together. Six to eight angels is an ideal number of angels.
This population size will allow individual angelfish to hang out and move in groups as these fish do in their natural habitats.
Remember that angelfish have complex social hierarchies and are potentially aggressive. If you have several individuals in the same aquarium, provide sufficient space and food to prevent conflict between them and to ensure that smaller fish don’t lose out at feeding time.
Providing enough room for a shoal of angelfish is also critical because the fish need space to grow. Angelfish grow to a large size with long anal and dorsal fins and reach a height of about one foot!
Angels require an extra 16 to 18 inches of space to grow properly.
Fish-keepers with decades of accumulated experience recommend that a 29-gallon (or larger) aquarium is necessary to house a shoal of between six and eight juvenile angelfish.
If you have the same number of mature angels, experts recommend a minimum tank volume of 55 to 75 gallons.
Keep Angelfish With Other Shoaling Fish
It is also possible to keep angelfish with other shoaling fish if you’d prefer to avoid the potential conflicts and complications associated with having multiple Pterophyllum scalare in the same tank.
You can keep one or two angelfish in a community tank with other species that have the shoaling habit.
Selecting the appropriate tank mates for angelfish is crucial. Angelfish may eat or bully small fish like neon tetras and guppies, so it is best to choose medium-sized tank mates.
Aquarium experts recommend the following fish for angelfish to live and shoal with:
- killifish
- corydoras
- mollies
- bushynose catfish
- Otocinclus catfish
- loaches
- flame tetras (and other Hyphessobrycon species)
There are also certain types of fish to avoid if you wish to ensure that angelfish are part of a peaceful and harmonious shoal.
Knowledgeable and experienced fish-keepers advise against some tetras and barbs because they might nip your angels. These nibble-prone fish include:
- tiger barbs (Puntigrus tetrazona)
- tetras in the Astyanax genus
- Buenos Aires tetras
Experts also indicate that there are certain fish that are not suitable for angelfish to shoal with because their frenetic behavior may become a source of agitation and stress for P. scalare.
These small and highly-active fish include:
- rasboras
- barbs
- rainbowfish
- danios
Monitor Social Interactions In The Shoal
To support peaceful and healthy shoaling behavior among your angelfish, it is essential to monitor the social interactions between the individual fish in the shoal.
Observe the shoal diligently to determine whether larger fish are displaying aggression towards smaller ones.
Additionally, check to make sure that bigger-sized individuals are not preventing the little fish from accessing sufficient food.
Conversely, it is crucial for you to monitor the shoal to ensure the smaller fish are not so energetic that they are causing annoyance and stress for your angelfish.
Conclusion
Angelfish might seem like schooling fish, but they are not. These elegant and poised tropical freshwater fish naturally prefer to aggregate and swim in groups called shoals. However, this behavior is not schooling.
Angels are known as shoaling fish because they gather in loosely-organized aggregations, with individual fish moving with a measure of independence from the other fish in the shoal. In contrast to angelfish, schooling fish swim in unison with each other, following a highly synchronized movement pattern.