Do Harlequin Rasboras Jump?

Harlequin rasboras (Trigonostigma heteromorpha) occasionally leap out of the water, though jumping is not a natural behavior for these fish. In general, harlequin rasboras won’t jump unless they are responding to threats from larger predator fish, unfavorable water conditions, or excessive visual and auditory stimulation from their surroundings. 

Harlequin rasboras are not naturally inclined to jump. However, many fish-keeping enthusiasts report having harlequin rasboras leaping from their tanks onto the floor! Fortunately, these attractive tropical freshwater fish won’t jump unless they are exceedingly unhappy with their living conditions, so there are ways to prevent this problem.

Are Harlequin Rasboras In The Habit Of Jumping?

In the wild, harlequin rasboras live below the surface of the water. Jumping is not part of these fishes’ natural behavior.

The situation is slightly different for harlequin rasboras in aquariums. Harlequin rasboras that are healthy and happy will not usually display jumping behavior when kept in tanks. However, these pretty little fish might jump when distressed.

Three of the most common causes of distress for harlequin rasboras:

  • physical threats from other fish
  • unfavorable water conditions
  • sensory over-stimulation

Physical Threats From Other Fish

Harlequin rasboras may feel compelled to jump when physically threatened by larger, more aggressive fish.

While harlequin rasboras occasionally bully or even eat smaller fish, they are not immune from being subjected to similar treatment.

When kept in community tanks, harlequins might leap from the water in an attempt to escape if there are fish that are bullying them severely.

Another, more urgent motivation for harlequin rasboras to jump is if they are in danger of being eaten by bigger predator fish. Faced with the possibility of becoming food for another fish, rasboras often jump in an attempt to survive.

Here are some examples of fish that might try to bully or eat harlequin rasboras and potentially compel these smaller fishes to jump:

  • wolf cichilid (Parachromis dovii),
  • jaguar cichilid (Parachromis managuensis),
  • opaline gourami, (Trichopodus trichopterus).

Water Conditions

Another common factor that can lead harlequin rasboras to jump is unfavorable water conditions.

Harlequins are hardy fish. However, if the condition of the water in their aquarium is unsuitable and causes the fish to become stressed, the animals might start jumping.

Harlequin rasboras are most likely to jump in a bid to exit their tank when the water is not within the following parameters:

  • temperature – 74 to 82F,
  • pH – 6.0 to 7.5 (6.5 is ideal),
  • salinity – low (avoid brackish water),
  • hardness – soft (2 to 15 dGH),
  • filtration – high filtration for clean water,
  • current intensity – mild.

When one or more of these parameters are outside of the ranges preferred by harlequin rasboras, there is a risk that the fish might start leaping out of the water.

Jumping is often observed in harlequins when the fish are added to a tank and have not been properly acclimated to the water in their new home.

The sudden change in water conditions can shock and stress harlequin rasboras and might prompt the fish to start jumping out of the water.

Harlequin Rasbora In Very Cloudy Water

Sensory Over-Stimulation

Harlequin rasboras may potentially jump when they experience sensory over-stimulation.

Jumping is often observed in harlequins when one adds the fish to a tank. This stress-induced behavior occurs when the fish have not had the chance to acclimate to the water in their new home.

The sudden change in water conditions can shock and create stress for harlequin rasboras and might prompt the fish to jump out of the water.

How To Prevent Harlequin Rasboras From Jumping

How can we prevent our harlequin rasboras from jumping and support their natural preference to remain below the water’s surface?

  • Maintain suitable water conditions,
  • provide compatible tank mates,
  • keep a lid on the tank,
  • position the tank in a peaceful location.

Maintain Suitable Water Conditions

Providing suitable water conditions in the aquarium is a primary requirement for preventing harlequin rasboras from leaping from their tanks.

Proper maintenance of harlequin rasboras’ preferred water temperature, pH, hardness, salinity, and filtration levels will support their health and well-being. Consequently, the fish are more likely to stay underwater.

When introducing harlequin rasboras to an aquarium, it is vital to let the fish acclimatize to the water. Harlequins that do not have the opportunity to adjust gradually to the tank water might start to perform aerial acrobatics.

Provide Compatible Tank Mates

You can dissuade harlequin rasboras in a community aquarium from jumping by ensuring they have compatible tank mates.

As highlighted earlier, large and aggressive fish species are generally not ideal tank mates for harlequin rasboras.

These incompatible fish may bully or attempt to eat the harlequins. Consequently, you might find yourself picking up harlequin rasboras from the floor in the vicinity of the tank!

To dramatically reduce the risk that harlequin rasboras will start exhibiting jumping behavior, it is advisable to keep them with fish such as:

  • platy (Xiphophorus spp.),
  • kuhli loach (Pangio kuhlii),
  • cherry barb (Puntius titteya),
  • Bolivian ram (Mikrogeophagus altispinosus),
  • neon tetra (Paracheirodon innesi).

Keep A Lid On The Tank

A guaranteed method for preventing harlequin rasboras from jumping is to keep a lid on the tank!

A lid (or plenty of plants) above the tank is beneficial when introducing harlequins to an aquarium.
However, if your harlequin rasboras are jumping, it is advisable to determine the underlying reasons for their behavior.

Position The Tank In A Peaceful Location

As we learned previously, harlequin rasboras are nervous fish that might start jumping when they experience an overload of sensory stimulation.

To discourage the fish from jumping, keep their tank in a relatively quiet place that does not have harsh lighting.

Positioning the tank away from people and curious furry and feathered animals will also lower the probability of the harlequins making a skyward exit from their tank!


When living in their natural habitat, harlequin rasboras are not in the habit of jumping. However, harlequin rasboras might start leaping from the water when these colorful, glittering tropical fish are residing in aquariums.

Harlequin rasboras are most prone to jumping when they are responding to stress or danger from poor water conditions, aggressive or predatory tank mates, and busy, noisy, or harshly lit environments.