It is unwise to keep full-grown angelfish in a 10-gallon or smaller tank. Angelfish are relatively large Cichlids, requiring a minimum tank of 29 gallons; however, larger tanks are better. If you plan on keeping two fish, your tank should be at least 30 gallons.
Unfortunately, many people keep angelfish in undersized tanks. Keeping Angelfish in inadequately sized tanks causes complications, and many aquarists recommend a larger tank for several reasons.
Why You Cannot Keep Angelfish In A 10 Gallon Tank
Although you could keep an Angelfish (Pterophyllum spp.) in a smaller tank (like 10 gallons), many agree it is not in the fish’s best interest.
Angelfish (like many other Cichlids) originate from the tropical waters of South America, where they inhabit river systems. Within these systems, angelfish have plenty of space for swimming.
The quintessential reason for keeping angelfish in a larger tank is that larger tanks result in less stress on the fish. A less stressed fish is a healthier, less aggressive fish that usually does not develop unwanted behaviors.
The Recommended Tank Size For Angelfish
Although several factors influence the aquarium size you’ll need for your angelfish; the minimum recommended tank size is 39.37 x 15.75 x 19.69 inches.
Some aquarists recommend a tank of 55 gallons (as this provides your angelfish with sufficient space); however, a tank of 29 gallons is sufficient for a single angelfish.
If you want to keep additional fish, the recommended minimum size is 30 gallons. This size tank supports two angelfish and a small number of other species.
The purpose of your angelfish and how many you’re keeping influence your tank size. If you’re breeding with angelfish or want to keep additional fish, your tank needs to be larger.
Angelfish Aquarium Requirements That Influence Tank Size
While an angelfish technically only needs 10 gallons of “space,” more space means you can better meet their needs, improving their living conditions, and benefiting any other species sharing the tank.
Below are some angelfish requirements and how they influence the minimum tank size you should use.
Physical Space Requirements
When fully grown, angelfish are roughly 6 inches long and up to around 8 inches tall. These medium-to-large Cichlids require enough space to stretch out their fins.
When kept in tanks of 10 gallons (or less), adult angelfish cannot use their fins to their full extent (i.e., they can’t extend their fins in a tank of fewer than 20 gallons).
Their larger height-to– length ratio means that angelfish also benefit from a taller tank.
Social Requirements
Although Cichlids (Angelfish included) tend to be territorial and a mildly-aggressive species, they generally prefer to be in communal tanks (a mix of similar-sized and temperament fish species).
Many consider angelfish a “calm” cichlid; however, they often fight with members of their species. Males are particularly “ornery” toward one another, especially those of breeding age.
If you determine to keep more than one angelfish in your aquarium, working on 10 gallons of water (space) per fish is a good idea. They are less likely to fight one another/other fish with more space.
A larger tank means that the angelfish have enough space to establish and defend territories while reducing conflict with members of their and other species.
Although they make suitable community fish, they might eat smaller fish, like neon tetras.
“Habitat” Requirements
Although the angelfish you keep in a home aquarium are usually domesticated (and born in captivity), they retain some of their “wild” characteristics.
Domesticated angelfish have similar habitat requirements to wild individuals. Cichlids (like angelfish) appreciate decorations and plants in their tank, including:
- Driftwood
- Large broad-leaved plants (specifically Amazon sword plants)
- Rocks
- Gravel substrate to facilitate foraging
In their natural habitats, angelfish live in dense underwater vegetation. For these fish to feel “at home,” you’ll need a sufficient amount of vegetation, rocks, and driftwood.
A larger tank accommodates more objects, which provides additional “hiding places” for your angelfish and other fish species.
A smaller tank limits the amount of extra “stuff” you could add before the tank becomes too cluttered to swim in.
Angelfish are omnivores and won’t pass up the chance to eat smaller fish, so with enough space and shelter, you help reduce the tank’s overall stress levels (by allowing fish to hide).
The Risks Of Keeping Angelfish In A 10 Gallon Tank
Although you could keep an angelfish in a smaller tank, this decision has some consequences.
These consequences include:
Increased Stress For All Fish Present
The essential drawback to keeping angelfish in a small tank is that they become stressed. Stress is a significant factor all hobby aquarists must consider/be aware of and mitigate.
Stress in a fish tank results in many additional issues developing between fish.
Increased Territorial Disputes
Should you decide to keep more than one fish in a 10-gallon tank (or overstock any size tank), territorial fish will become a significant issue for you and your tank.
As more fish enter the angelfish’s territory, it’ll attack intruders. This aggression is bad for several reasons.
- Fish injure each other when they fight, which becomes problematic.
- The territorial fish (e.g., angelfish) “burns out” quicker. They’re constantly stressed from chasing away intruders.
- The development of undesirable behaviors like fin-nipping, destroying the habitat, not eating properly, attacking your hand when you try to clean the tank, etc.
A Reduction In Fish Longevity And Quality Of Life
Increased stress throughout your tank’s denizens results in fish living shorter lives, not producing healthy offspring, and being more susceptible to diseases.
You’ll need a larger tank if you keep other aggressive fish or “fin-nipping” species. A Larger tank means that less aggressive fish can move away.
Larger tanks mean you can add more decorations/habitats (for hiding) and distribute food more evenly, so slower species (like angelfish) can access it.
When Could You Keep Angelfish In A 10 Gallon Tank?
It’s not good aquarist practice to keep fish in smaller tanks; however, under certain conditions, you could consider a smaller tank, including:
- Although many experts recommend keeping your juvenile and subadult angelfish in a larger tank, while angelfish are growing, you can keep them in a 10-gallon tank.
However, you’ll need to transfer them to a larger tank as the angelfish grow.
- If all you have available is a 10-gallon tank, then that will have to be sufficient until you can purchase a tank large enough to accommodate your fish.
- If you have a sick or injured fish that you need to quarantine, then placing them in a 10-gallon tank is okay until the fish is well enough to return to their larger tank.
- When cleaning your tank and you need to temporarily house your fish, a 10-gallon tank would be suitable (most people don’t have the budget to purchase many large additional tanks).
Recommended Angelfish Tank Mates
Cichlids are renowned for their territorial behavior, so choosing tank mates is not always easy. Angelfish are often the targets of aggressive/fin-nipping fish. Aside from pairing fish with similar behavior, you’ll also need to select fish with similar habitat needs, including tank size.
The best tank mates for angelfish are large, hardy, peaceful fish.
Some recommended Cichlid tank mates include:
- Black Skirt Tetra
- Common Pleco
- German Blue Ram
- Keyhole Cichlids
- Mollies
- Silver Dollar
- Swordtails
When selecting tank mates, it would be wise to keep in mind:
- Adult size (how big the fish grow)
- Care level (don’t take on more than you can handle)
- Social requirements (are they community fish, and how many of the same species do they need)
- Temperament (are they aggressive)
When keeping angelfish in a community tank, bigger is better. Although a 30-gallon tank would serve your purposes, a 55-gallon tank is preferable.
Conclusion
Although you could keep a single angelfish in a 10-gallon tank, many aquarists recommend against this practice. The minimum size tank for one angelfish is between 20 and 30 gallons.
You’ll need to add 10 gallons per fish if you plan on keeping additional fish. Your purpose in keeping the angelfish, the tank community/diversity (and their collective requirements), determine the tank’s size requirements.