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Lionfish are solitary creatures and quite popular with aquarists. Be careful handling lionfish, since their dorsal spines are venomous and can feel like a strong bee sting.


Lionfish Facts

Average Adult Size 6 to 18 inches long, depending on species
Average Life Span depends on species
Diet carnivore
Minimum Aquarium Size 50+ gallons, depending on species
Water Temperature: 72-78°F
Salinity Level: 1.020-1.026


A well-balanced Lionfish diet consists of:

  • Frozen food (silversides, krill, squid) and freezedried krill.
  • May need to feed live food and transition over to frozen food or freezedried krill.
  • Vary diet to ensure proper nutritional balance.


Things to remember when feeding your Lionfish:

  • Feed 1 to 2 times a daily.
  • If necessary, feed live fish in the beginning, gradually enticing them to eat other foods.
  • Thaw frozen food before feeding.


  • Keep in an appropriate size aquarium; provide rock and decor for hiding places and plenty of room for movement.
  • Stable water quality, water temperature, and pH levels are critical to the health of the aquatic life. If you are unsure of your water quality or pH levels, Petco provides free water testing.

Normal Behavior

  • Mostly solitary, not a very active swimmer.
  • Lionfish attack their meal in one swift motion.
  • Use caution: dorsal spines are venomous and can feel like a strong bee sting; although most people are not affected by lionfish stings, some humans may be allergic to the venom.

Habitat Maintenance

  • 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 to 4 weeks, or as needed.
  • Introduce new inhabitants to the aquarium gradually.
  • Be aware of the lionfish’s location within the tank when performing maintenance to avoid getting stung.


  • Compatible with fish of similar or larger size; will eat smaller fish.
  • Check Petco's Marine Compatibility Care Sheet detailed information for each large marine fish species.


Signs of a Healthy Fish

  • Clear eyes
  • Healthy appetite
  • Bright, even coloring
  • Swims slowly

Avoid overcrowded conditions; they are a major cause of stress and disease. Maintain good water quality with regular water changes and adequate filtration.

Red Flags

  • loss of color
  • spots or fungus on body or mouth
  • erratic swimming
  • labored breathing
  • cloudy eyes
  • weight loss

Common Health Issues

Health Issue Symptoms or Causes Suggested Action
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 lionfish 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.

Go to the Centers for Disease Control at for more information about aquatic life and disease.

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.