Bettas And Harlequin Rasboras: Are They A Good Fit?

So you’re thinking about adding bettas harlequin rasboras together! Well you’ve found the right article. Keep reading to find out why they’re so compatible, as well as what to do to increase the chances of peace and harmony in your tank!

Can Harlequin Rasboras And Betta Fish Live Together?

Absolutely, Harlequin Rasboras and Betta fish can make good tank mates under the right conditions. However, there are several factors to consider such as tank size, water parameters, and individual fish temperament. If done properly, the two species can coexist peacefully and even thrive.

Harlequin RasborasBetta Fish
AppearanceHarlequin Rasboras have an eye-catching, orange-copper body, highlighted by a unique black “wedge” that starts near the dorsal fin and narrows toward the tail.Bettas are vividly colored with flamboyant fins, available in a wide range of hues like classic blues and reds, as well as exotic patterns.
Life ExpectancyThese fish are quite hardy and can live between 5 to 8 years when well taken care of. Key factors include diet, water quality, and minimal stress.Bettas generally live up to 3-5 years in optimal conditions. Though they often start life in less-than-ideal pet store conditions, proper care can prolong their lives significantly.
BehaviorHarlequin Rasboras are social and peaceful schooling fish. They are happiest in groups of six or more and typically stick to the top or middle levels of the tank.Bettas have a feisty reputation but usually get along with non-aggressive and dissimilar-looking fish. Males can be territorial but are generally peaceful towards fish like Harlequin Rasboras.

Betta Water Conditions

In the wild, betta fish inhabit the warm, slow-moving or stagnant waters commonly found in Southeast Asia, especially in countries like Thailand, Cambodia, and Vietnam. These waters usually have temperatures between 75-82°F (24-28°C).

  • pH Levels: Approximately 6.0-7.5, leaning towards slightly acidic to neutral conditions
  • Water Hardness: Typically soft
  • Water Flow: Generally low to moderate

Vegetation and Shelter

Bettas often find shelter among dense aquatic vegetation, which provides natural hiding spots and doubles as a location for bubble nest building.

  • Common Plants: Water hyacinth, water lettuce, and various ferns are among their favorites.
  • Additional Shelter: In their natural habitat, fallen branches, roots, and reeds often offer extra cover.

Harlequin Rasbora Water Conditions

Harlequin Rasboras are naturally found in the flowing streams and rivers of Southeast Asia, with a focus on countries like Malaysia, Singapore, and Thailand. The water temperature in their habitat typically ranges from 73-82°F (22-28°C).

  • pH Levels: The pH usually falls between 6.0 and 7.0, making it slightly acidic to neutral.
  • Water Hardness: Generally soft to moderately hard
  • Water Flow: Moderate, reflecting their stream-based habitat

Vegetation and Shelter

In the wild, Harlequin Rasboras seek out well-planted areas that offer ample hiding spaces and also serve as good spots for foraging.

  • Common Plants: Various species of Cryptocoryne, ferns, and other native aquatic plants.
  • Additional Shelter: They often find cover among submerged tree roots and driftwood.
Betta FishHarlequin Rasbora
Geographic LocationSoutheast Asia (Thailand, Cambodia, Vietnam)Southeast Asia (Malaysia, Singapore, Thailand)
Temperature Range75-82°F (24-28°C)73-82°F (22-28°C)
pH Levels6.0-7.5 (slightly acidic to neutral)6.0-7.0 (slightly acidic to neutral)
Water HardnessSoftSoft to moderately hard
Water FlowLow to moderateModerate
Common PlantsWater hyacinth, water lettuce, various fernsCryptocoryne species, ferns, and other native aquatic plants
Additional ShelterFallen branches, roots, reedsSubmerged tree roots, driftwood

Making It Work: Tank Conditions

Creating a compatible environment for both Betta fish and Harlequin Rasboras requires thoughtful planning. Here’s how you can set up a harmonious tank that accommodates the needs of both species.

Tank Size

For Betta fish, a minimum of a 5-gallon tank is often recommended, but Harlequin Rasboras are schooling fish that need more space. Aim for at least a 20-gallon tank to provide ample room for both species to flourish.

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Water Movement

Bettas prefer low to moderate water flow, matching their natural slow-moving habitats. Harlequin Rasboras are accustomed to moderate flow, as they’re from stream environments. A filter with adjustable flow can help strike a balance that suits both species.

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Water Parameters

Both fish thrive in warm, slightly acidic to neutral water. Keep the temperature between 76-80°F, with a pH level ranging from 6.5 to 7.5. Regular water testing is crucial to ensure these parameters are maintained.

Tank Decorations

Here’s where you can get creative. Both species appreciate well-planted tanks. Opt for plants like Cryptocoryne or water ferns that can serve both as hiding spots and foraging areas. Adding driftwood and rocks can provide additional shelter and mimic their natural habitats.

Diet & Nutrition

Betta fish are primarily carnivorous, loving foods like brine shrimp and daphnia. Harlequin Rasboras are omnivores that enjoy a mix of plant matter and protein. So offering a varied diet that includes flakes, pellets, and occasional live or frozen foods for your rasboras, and betta pellets for your betta is the key to success.

Harlequin Rasbora And Bettas Together

How To Introduce Harlequin Rasboras & Bettas

Introducing these two species to the same tank needs to be done with care to ensure a smooth transition and long-term compatibility.

Bettas or Harlequin Rasboras First?

It’s generally a good idea to introduce the Harlequin Rasboras to the tank first. This allows them to establish their territory and get comfortable without the presence of a potentially territorial Betta.

After the Rasboras have settled in—typically a week or so—you can introduce the Betta fish. Doing it this way minimizes the chances of territorial disputes.

Problems Keeping Harlequin Rasboras & Bettas Together

Although these two fish are generally compatible, there can be some issues. Bettas are known for their territorial behavior, and sometimes, they may show signs of aggression toward the Harlequin Rasboras. Overcrowding can exacerbate this, as can a lack of hiding spots.

How To Deal With An Aggressive Betta?

So you’ve noticed your Betta’s getting a little feisty? Don’t worry; there are steps you can take:

  1. Separation: Temporarily move the Betta to another tank. This “time-out” can help reset its territorial instincts.
  2. Rearrange the Tank: Mix up the layout of the tank decorations and plants. This disrupts established territories and may reduce aggression.
  3. Monitor Closely: When reintroducing the Betta, keep a close eye on its behavior. If aggression persists, permanent separation might be necessary.
  4. Consult an Expert: Sometimes, it’s helpful to consult with someone more experienced to find a tailored solution for your specific Betta.
  5. Use a Tank Divider: If no matter what, you can’t get your betta and harlequin rasboras to get along, then you will most likely need to use a tank divider to separate them permanently.

What Other Fish Go Well With Harlequin Rasboras And Bettas?

If you have a big enough tank, then you’re probably going to want to keep more than just bettas and harlequin rasboras. However, it’s essential to choose tank mates wisely to keep the peace.

  1. Corydoras: These peaceful bottom dwellers will stay well out of the way of your betta and rasboras. They also help keep the substrate clean and add another layer of activity to your setup.
  2. Neon Tetras: They’re colorful, small, and non-aggressive, making them another excellent candidate. Just ensure that you have a large enough tank to accommodate them, as they can become a bit nippy.
  3. Ghost or Cherry Shrimp: These invertebrates can provide a different type of interest and also help to keep the tank clean. However, make sure there are plenty of hiding spots, as they can become a snack for a hungry Betta.
  4. Otocinclus Catfish: These algae eaters will mind their own business and won’t mess with other fish and can help keep your tank clean.
Harlequin Rasboras And Bettas


Alright, let’s wrap this up. In my years of fishkeeping, I’ve found that Harlequin Rasboras and Bettas generally make good tank mates. The key lies in the setup and introduction process.

It’s usually best to introduce the Rasboras first to give them a head start in acclimating to their new environment. Then, bring in the Betta to minimize territorial issues. Trust me, if you do it the other way round, you’re much more likely to run into bother.

As for additional teammates, I’ve had the most success with corydoras catfish, however, shrimp and snails are also a great choice!

And remember to make sure you’re keeping tabs on water parameters and tank conditions.

So there you have it. With proper planning and ongoing care, you can create a balanced and peaceful community tank that both you and your fish will love. Happy fishkeeping!

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