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Rasbora Care Sheet

Developed with and approved by a qualified veterinarian.


This care sheet covers a variety of rasbora species, including: 

  • Harlequin rasbora
  • Scissortail rasbora
  • Brilliant rasbora  
  • Lambchop rasbora 
  • Hengelii rasbora  
  • Brigittae rasbora  
  • Dwarf emerald rasbora  
  • Redline rasbora 
  • Axelrod rasbora 
  • Green kubotai rasbora  



Trigonostigma heteromorpha, Rasbora trilineata, Rasbora borapetensis, Trigonostigma espei, Trigonostigma hengelii, Boraras brigittae, Microrasbora erythromicron, Rasbora pauciperforata, Sundadanio axelrodi, Rasbora kubotai 

Generally quiet and nonaggressive, many rasboras are brightly colored schooling fish who shimmer in the light. Native to Southeast China, South and Southeast Asia, rasboras have striking coloration and patterns and inhabit the mid to lower part of the aquarium. Most species are recommended for beginning aquarists due to their hardiness and compatibility with other aquatic life. 


Typical appearance and behavior  

  • Schooling fish are happiest in groups of five or more of the same species in odd numbers. 
  • Rasboras feel more secure when plenty of plants and hiding places are provided 
  • Rasboras generally have a peaceful temperament and can get along with most community fish 
  • They come in a variety of patterns and colors, several resembling some tetra species 
  • They prefer a planted tank with décor and slow to moderate current 
  • Many rasbora species are good jumpers, so provide a secure lid for the aquarium 



Care Difficuty Beginner to intermediate, depending on species
Average Life Span Up to 8 years with proper care, depending on species.
Average Adult Size ¾–6”, depending on species
Diet Omnivorous
Minimum Habitat Size 10+ gallons, depending on species
Water Temperature 72-82°F



Habitat size 

Keep in an appropriately sized aquarium, which can range from 10 gallons for a small school of a smaller species of adult rasboras to a much larger aquarium for a large school or larger rasbora species.  

Building your habitat 

  • Water health - 
    • Provide proper filtration to ensure optimal water quality to help maintain health 
    • Provide slow to moderate water circulation to mimic the water currents and high oxygen levels found in a rasbora’s natural habitat 
    • Stable water quality (pH, ammonia, nitrate, nitrite) and water temperature are critical to the health of aquatic life; if you are unsure of your water quality, bring a sample to Petco for free testing 
    • Use an aquatic heater to stabilize water temperature, ensuring it does not fluctuate more than 2 degrees in either direction in a 24-hour period 
    • Many rasboras will benefit from the addition of freshwater salt to the aquarium; the specific gravity should be kept at 1.004 
    • Always research your species-specific needs before adding freshwater aquarium salt, and do not allow specific gravity to fluctuate more than 0.001 in either direction in a 24-hour period 
  • Décor - 
    • Provide plenty of space for swimming as well as plants, rocks or decor for hiding places 



A well-balanced rasbora diet consists of: 

  • Tropical flakes, pellets, freeze-dried or frozen foods 
  • Treats like bloodworms, brine shrimp and mysis shrimp (frozen or freeze-dried) 

Things to remember when feeding your rasbora: 

  • Feed 1–2 times a day, no more than will be eaten within 1–2 minutes 
  • Thaw frozen food before feeding 


Rasbora care 

  • Maintaining great water quality with regular water changes and adequate filtration is important to help keep your rasbora healthy 
    • Daily: Check filter, water temperature and other equipment 
    • Weekly: Test water quality at least once a week 
    • Weekly to monthly: Change 10–25% of the total volume of water every 2–4 weeks, or as needed; change filter media monthly 
  • Avoid overcrowded conditions; they are a major cause of stress and disease 


Where to buy rasboras

Various rasbora species are available for purchase at Petco online and in-store, availability varies by location. If visiting your local location, please call ahead to check availability. 




Tank mates 

  • Compatible with:
  • Other Rasboras
  • Catfish
  • Danios
  • Guppies
  • Hatchets
  • Killifish
  • Mollies
  • Platies
  • Smaller plecos
  • Swordtails
  • Tetras
  • May be compatible with less aggressive barbs and gouramis
  • Introduce new inhabitants to the aquarium gradually



Signs of a healthy rasbora 

  • Clear eyes 
  • Healthy appetite 
  • Bright, even coloring 
  • Fins completely intact and undamaged 
  • Free of parasites or disease 


Red flags (if you notice any of these signs, contact your local aquatic specialist or aquatic veterinarian) 

  • Loss of color or appetite 
  • Spots or fungus on body or mouth 
  • Cloudy eyes or pop-eye 
  • Frayed fins 
  • Labored breathing 
  • Erratic swimming 
  • Weight loss 
  • Bloating 
  • Listlessness  


Common rasbora health issues 

Health Issue Symptoms or Causes Suggested Action
Health IssueFin rot Symptoms or CausesFrayed or disintegrating fins; the base of the fins usually reddens. Suggested ActionImprove water quality; consult your local aquatic specialist or aquatic veterinarian for treatment.
Health IssueIch Symptoms or CausesWhite spots appear on fins and body; fish rubs against hard objects or swims erratically; rapid respirations Suggested ActionQuarantine fish immediately; add freshwater salt and use a commercial ich remedy as directed;. consult your local aquatic specialist or aquatic veterinarian for treatment.
Health IssueFungus Symptoms or CausesWhite cottony growth and/or discoloration of the eyes. Suggested ActionQuarantine fish; use a commercial antifungal remedy as directed; consult your local aquatic specialist or aquatic veterinarian for treatment.
Health IssueBacterial infections Symptoms or CausesCloudy eyes, open sores and/or reddening of the skin. Suggested ActionImprove water quality; add freshwater aquarium salt; use a commercial antibacterial remedy as directed; consult your local aquatic specialist or aquatic veterinarian for treatment.
Health IssueCottonmouth or columnaris Symptoms or CausesCottony white growths along the body and/or gills, frayed fins and gills turn brown and necrotic in late stages; caused by bacterial infection. Suggested ActionQuarantine fish; improve water quality; lower aquarium temperature to 72°F to deter bacteria from growing; medicate as directed; consult your local aquatic specialist or aquatic veterinarian for treatment.



  • How big do harlequin rasboras get? Most rasboras stay small, but a few species get larger; rasboras reach an average adult size of ¾–6”, depending on species.  
  • How many rasboras can live in a 10-gallon aquarium? The number of rasboras who can be housed in a 10-gallon aquarium will vary by species and their adult size. Remember rasboras are a schooling fish, so a 10-gallon aquarium could house a small school of 5 fish for a smaller rasbora species like the harlequin rasbora.  
  • How many rasboras should be in a school? A minimum of 5 rasboras should be kept in a school, and schools of fish should always be odd numbers.  
  • How big do scissortail rasboras get? Scissortail rasboras can reach an adult size of 6”.  


Additional Care Sheets

Notes and resources

Ask a Pet Care Center associate about Petco's selection of products available for the care and happiness of your new pet. All products carry a 100% money-back guarantee.

Because all aquatic life are potential carriers of infectious diseases, such as atypical mycobacterium and salmonella, always wash your hands before and after handling your aquatic life or habitat contents to help prevent the potential spread of disease.

Pregnant women, children under the age of 5, senior citizens and people with weakened immune systems should contact their physician before purchasing or caring for aquatic life and should consider not having aquatic life as a pet.

Go to for more information about aquatic life and disease.

The information on this care sheet is not a substitute for veterinary care. If you need additional information, please contact your veterinarian as appropriate.