Emerald Eye Rasbora (Rasbora dorsiocellata): Ultimate Care Guide

The Emerald Eye Rasbora (Rasbora dorsiocellata) also known as Eyespot Rasbora, is a delight to watch. As its name suggests, this fish is like the crowning jewel of an aquarium. Their main color is silver and they hold a hue of blush pink near their center. Sometimes, if the light reflects off them just right you can see a greenish-gold stripe stretching from their gill cover to their tail. Its shimmering long body and eye-catching yellow dorsal fin with a black spot on it give this species of Rasbora its unique, visual, appeal. The real magic of these fish is their eyes, which appear to have a beautiful green glow to them. Emerald Eye Rasboras are schooling fish. They originate from the streams and tributaries of Asia. Sadly their natural habitat is under threat from palm oil plantations.

Emerald Eye Rasbora Care

Rasboras in general are a very hardy fish and Emerald Eye Rasboras are a particularly hardy species of Rasbora. Because of their hardiness, Emerald Eye Rasboras are not high maintenance with it comes to water conditions. They are happy in a tank that is 73 and 79 degrees Fahrenheit. The water PH should be between 3 and 7. Emerald Eye Rasboras are soft-water fish.

Be on the lookout for rising nitrate levels in the water as Emerald Eye Rasboras can be quite sensitive to that. When introducing them to your tank, acclimatize them very carefully. Swings in water chemistry could be detrimental to the fish.

Have an aquarium filter that employs the three main types of filtration. Mechanical, chemical, biological. Emerald Eye Rasboras are quite strong swimmers, but they definitely prefer waters on the calmer side.

The Emerald Eye Rasbora is best suited to a mature freshwater tank. In the wild, they seek out areas with a heavy plant density and slow-moving black water. If images of shallow forest brooks and peat swamps come to mind, your stream of thought is very accurate.

Emerald Eye Rasbora (Rasbora dorsiocellata)
Emerald Eye Rasbora (Rasbora dorsiocellata)

This is why a well-established aquarium is the right home for your Emerald Eye Rasboras. They’re not keen on bright light so having plenty of shady spots with well-developed plants. Driftwood that resembles large tree roots is also a nice addition for the Rasboras to find shelter from the aquarium lights. A dark substrate on the bottom of the tank is also recommended.

If you’d like to have your aquarium take on a different aesthetic Emerald Eye Rasboras thrive in a more natural setting. Think soft, sandy, bottom. Various pieces of driftwood placed strategically in the tank to create shady, hiding areas.

Even dried leaf litter can be added. The leaves add extra shade and as they decompose they offer microbes to the environment. These microbes can be an alternative food source to baby Emerald Eye Rasboras.

Another benefit of decomposing leaves is the tannins and other chemicals they release into the water are very beneficial to the adult fish.

Since Emerald Eye Rasboras are fans of shade, as well as dark and murky water, choose a light that will benefit the plants they’re keen to seek refuge under, as well as a light that will mimic the natural light they would receive in nature.

Good news for aquarium enthusiasts, when given the proper care and attention, Emerald Eye Rasboras can live 4-6 years.

Emerald Eye Rasboras are small fish, reaching a maximum of 4cm (1.6”). This makes them quite timid and apt to hide in the tank. It’s best to have 10 or more fish to form a school. Emerald Eye Rasboras enjoy a large amount of free swimming space, taking up the middle to top of the tank, so housing 10 of them with other compatible fish requires a 30 gallon or larger aquarium. If you’re planning to have only a small school of Emerald Eye Rasboras (up to 5) you could use a 20 gallon tank.

Emerald Eye Rasbora Tank Mates

Having a school of Emerald Eye Rasboras helps them feel more secure. It also creates some competition for the males to attract female attention and they will display their most attractive colours.

Emerald Eye Rasboras are peaceful fish. In addition to living with others of their kind, they also make excellent tank mates with other small peaceful fish. The list includes small Cyprinids, Tetras, Livebearers and Dwarf Cichlids,Catfish, loaches, and Caridina and Neocaridina shrimp.

Betta fish are not the best species to have in a tank with Emerald Eye Rasboras. Because of the Emerald Eye Rasboras’ flashy green eye, Bettas may be tempted to strike out at them.


It’s best not to be squeamish when feeding Emerald Eye Rasboras. They are omnivores and eat a varied combination of foods including:

  • Crushed flakes and micro pellets to satisfy their plant-based needs.
  • Mini-bloodworm
  • White mosquito larvae
  • Baby brine shrimp
  • Cyclops Frozen Fish Food which contains small, fresh-frozen zooplankton
  • Daphnia. Note: Daphnia are small planktonic crustaceans, They’re are a great natural source of algae and also act as an excellent laxative for fish. They can be purchased freeze dried, frozen, or live. You can even cultivate your own Daphnia, but that’s a topic for another article.


Emerald Eye Rasboras are egg scatterers and constant spawners. Mature adults will drop a few eggs daily. In a regular well planted aquarium the eggs will cover plants and decor. The tiny size of the eggs and resulting larvae will be seen as food by the adult fish and, likely, they will not survive. It is possible if there is enough coverage for a small number of offspring to grow into fry and then survive to adulthood.

If you’re looking for a more successful breeding setup and a larger yield of fry, a separate breeding tank will be required.

This tank should be dimly lit. The bottom should contain mesh that the adult fish can not swim through, but the eggs can pass through so they are protected from the breeding pair. As an alternative to mesh, marbles, plastic grass matting or pebbles have also shown to be successful.

Adjust the temperature of the breeding tank to slightly higher than the regular tank and the water should have a mildly acidic to neutral PH.

Now it’s time to introduce the breeding pair to the breeding tank. This means accurately sexing the fish which can be somewhat difficult with Emerald Eye Rasboras. Females are marginally larger than males. They also have a rounder belly that is quite noticeable. Males sometimes sport a pinkish hue on their tails during mating season.

When the female looks swollen with eggs it’s time to place one or two couples in the breeding tank. Small amounts of water at a lower temperature can be added to the tank every few hours to encourage spawning. The fish in the breeding tank should be fed frozen and live food three to four times throughout the day.

Since Emerald Eye Rasboras are total “fins off” parents, they don’t have any attachments to their eggs and will eat any they find. The adult Emerald Eye Rasboras can be removed from the breeding tank and replaced in the regular tank in a day or two. Protecting the little ones from harm.

The incubation period for the Emerald Eye Rasbora eggs is dependent on the temperature of the water. The usual time for the eggs to hatch is 18-48 hours. The newly hatched Emerald Eye Rasboras will be swimming about the tank within 48 hours.

The fry should be provided paramecium or infusoria in the early stages. They can move on to baby brine shrimp and microworm once they’ve grown enough to consume them.

Common Diseases

As with any living being you choose to have in your home, Emerald Eye Rasbora can come in contact with a variety of diseases. Most of these diseases are very difficult to cure. The best way to battle them is through prevention. The main causes of fish illness are the quality of water, stress, the temperature of the water, ammonia, and dissolved oxygen.

Here are some health tips for keeping Emerald Eye Rasboras:

  • The most important action for prevention is keeping the water in your tank healthy. Monitor the PH and ammonia levels frequently. This will greatly reduce your Emerald Eye Rasbora’s chances of getting sick.
  • Make sure your filter is adequate to keep up with the size of your tank.
  • Emerald Eye Rasbora needs a fully balanced diet. They require vitamins and protein-rich nutrients.
  • Do not overfeed your Emerald Eye Rasboras. If too much food accidentally gets into the tank, remove it from the container.

Below are some common diseases for Emerald Eye Rasbora:

Fungal infections are the most common disease for Rasbora. Signs of this include, white or grey patches on the skin and gills, the fish’s body turning brown or green, and a large, gooey mass growing out of the skin. It can be cured easily with appropriate care but has the potential to damage the fish’s brain, liver, and other vital organs, making the disease possibly fatal.

To treat fungal infections, eliminate the chlorine in the water using a water purifier. Raise the temperature of the water to 77F, isolate the infected fish and add one tbsp of aquarium salt to the isolation tank, malachite green, Potassium Permanganate, formalin, and povidone-iodine solutions can be helpful medications to successfully cure the fungus.

White spot or Ich is another very common Emerald Eye Rasbora disease. Ich can be identified by observing small crystals on the body that resemble salt, a slimy coating of the infected area, rapid breathing, and loss of appetite. Ich is highly contagious.

To treat Ich, increase the water temperature to between 71.6 and 86 degrees Fahrenheit. Anti-parasitic medication and Malachite green are highly recommended to cure this disease.

Fish lice can be found either attached to the body of your Emerald Eye Rasbora or swimming freely in your tank. They can infect the tank through new aquarium plants or fish that have not had a proper quarantine time before being introduced into the main tank.

If you notice your Emerald Eye Rasbora rubbing itself against hard surfaces and they’re looking pale, inflamed, and have redness, there could be a fish lice problem.

To rid your fish and your tank of fish lice, hold your Emerald Eye Rasbora in a moderately wet cloth and use tweezers to pick the lice off of it. Treat any red spots with Neosporin. Add one tbsp of aquarium salt to the tank water.


Emerald Eye Rasbora is a hardy and easy fish to have as part of your aquarium community. They’re beautiful and have interesting behaviours, especially when they are homed in a school of 10 or more. They’re peaceful fish and will entertain your eyes for years with a well-maintained environment and diet. Truly charming little aquatic friends to own.