Cardinal Fish have two distinct dorsal fins and can be found around the world. These slowmoving nocturnal fish make excellent additions to large community aquariums. Most species are recommended for beginning marine aquarists.
Cardinal Fish Facts
Average Adult Size
2 1/2 to 5+ inches long, depending on species
Average Life Span
depends on species
Minimum Aquarium Size
5+ gallons, depending on species
A well-balanced cardinalfish diet consists of:
Flakes, pellets, and frozen food.
Vary diet to ensure proper nutritional balance.
Things to remember when feeding your Cardinal Fish:
Depending on species and size, feed small amounts 2 to 3 times daily, no more than fish will eat in 1 to 2 minutes.
Thaw frozen food before feeding.
Keep in an appropriately sized aquarium; provide plants, rock and décor for hiding places and plenty of room for movement.
Stable water quality and parameters are critical to the health of aquatic life. If you are unsure of your water quality, Petco provides free water testing.
Peaceful, some species can be kept in small groups; different species should not be mixed.
Although nocturnal (active at night), cardinalfish can become used to daytime feeding and activity.
May become aggressive toward individuals of the same species; should be kept in groups of five or more.
Daily: Check filter, water temperature, specific gravity and other equipment.
Weekly: Check water quality at least once a week.
Monthly: Change 10 to 25% of the total volume of water every 2-4 weeks, or as needed. Introduce new inhabitants to the aquarium gradually.
Compatible with dwarf angelfish, blennies, clownfish and gobies. Can be compatible with large angelfish, damselfish, groupers, psuedochromis, tangs and wrasses.
May become aggressive in an overcrowded aquarium.
Signs of a Healthy Fish
Fins completely intact and undamaged
Avoid overcrowded conditions; they are a major cause of stress and disease. Maintain good water quality with regular water changes and adequate filtration.
loss of color or appetite
spots or fungus on body or mouth
If you notice any of these signs, contact your veterinarian.
Common Health Issues
Symptoms or Causes
Health Issue Fin rot
Symptoms or Causes Frayed or disintegrating fins; the base of the fins usually reddens.
Suggested Action Improve water quality; consult your aquatic veterinarian for treatment.
Health Issue Marine ich
Symptoms or Causes Cysts on fins, gills, and skin; labored breathing, excess skin mucus or pale skin.
Suggested Action Treat entire aquarium with a commercial parasite remedy and improve water quality; freshwater dips can dislodge the parasites.
Ask a store partner about Petco's selection of books on cardinal fish and the variety of private brand products available for the care and happiness of your new pet. All private brand 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.
This care sheet can cover the needs of other species.
Note: The information on this Care Sheet is not a substitute for veterinary care. If you need additional information, please refer to the sources on the following page or contact your veterinarian as appropriate.
Developed with and approved by a qualified veterinarian.
Free Standard Shipping automatically applies to your qualifying minimum online purchase subtotal of $49. No promotion code necessary. Subtotal refers to amount of order before taxes and shipping. All Free Shipping is based on Standard Shipping rates.
Free Shipping Exclusions: Cat litter, dog litter, ice melter, wild bird food, live fish & rock, aquatic gravel and accents; crickets, live food and frozen food; out-of-stock items, Donations, Petco or Unleashed by Petco Gift Cards and eGift Cards; items shipped through white glove delivery or LTL delivery; orders exceeding the maximum weight limit of 300 lbs.; and applicable taxes. Additional exclusions may apply and will be noted on the Product Detail page and/or Shopping Cart.
Cat litter, dog litter, wild bird food, live & frozen food and oversized items may incur an additional per-item shipping & handling fee or surcharge. Additional fees may apply and will be noted on the Product Detail page and/or Shopping Cart.
Did you know? Repeat Delivery orders always ship free. Learn More
20% off your first Repeat Delivery order Terms & Conditions
- The 20% discount is valid only on first-time Repeat Delivery orders.
- Enter promo code: rdsave20 in your Shopping Cart. Promotion codes are case and character sensitive, please enter as shown here.
- The 20% discount automatically applies to your first-time, qualifying Repeat Delivery purchase subtotal. Subtotal refers to amount of order before taxes and shipping. Maximum discount amount is $20.
- Exclusions: Add-on items, out-of-stock items, Donations, Petco Gift Cards and eGift Cards; items shipped through white glove delivery or LTL delivery; orders exceeding the maximum weight limit of 300 lbs.; and applicable taxes. Additional exclusions may apply and will be noted on the Product Detail page and/or Shopping Cart.
- Petco.com charges applicable tax on all orders shipped to states in which Petco has a physical location.
- Promotion Code valid for one use per order.
- Promotion Code cannot be redistributed or used in combination with any other offer.
- Petco.com in its sole discretion may refuse to redeem any Promotion Code that it believes in good faith to be fraudulently or improperly obtained.