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Brackish Water Fish

Brackish Water Fish

includes the archer, puffer, scats, monos and leaf fish

In their natural environment, Brackish Water Fish live where freshwater meets saltwater. In your aquarium a mixture of saltwater and freshwater is used. Brackish Water Fish are easy to feed and can readily adapt to various water conditions.

Brackish Water Fish

Brackish Water Fish Facts

Average Adult Size depends on species
Average Life Span depends on species
Diet omnivore
Minimum Aquarium Size 20+ gallons, depending on species
Water Temperature: 72-82°F
Salinity Level: 1.005-1.015


A well-balanced Brackish Water diet consists of:

  • Live or frozen foods, such as brine shrimp or bloodworms.
  • Flake and dried foods or vegetable matter.
  • Some are scavengers and will eat any leftover food or debris.


Things to remember when feeding your brackish water fish:

  • Depending on species, feed small amounts up to three times a day, no more than fish will eat in 3-5 minutes.
  • Thaw frozen food before feeding.


  • Keep in an appropriate size aquarium; provide plenty of plants, rocks or decor for hiding places.
  • 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.


  • Archer fish can jump out of the water or spit water to catch insects.
  • Brackish puffers are similar to saltwater puffers in appearance, however, most species are smaller than their saltwater cousins.
  • Scats come in a variety of colors and patterns.
  • Monos have a very unique diamond shaped body.

Habitat Maintenance

  • Daily: check filter, water temperature and other equipment.
  • Weekly: check water quality at least once a week; check salinity levels at least twice a week.
  • Monthly: change 10-25% of the total volume of water every 2-4 weeks, or as needed.
  • Introduce new inhabitants to the aquarium gradually.


  • Compatible with similar size Brackish Fish. Can be compatible with invertebrates or crustaceans.


Signs of a Healthy Fish

  • Clear eyes
  • Healthy appetite
  • Bright, even coloring
  • Clean in appearance

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 appetite
  • spots or fungus on body or mouth
  • listlessness
  • labored breathing

If you notice any of these signs, contact your veterinarian.

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 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 an associate about Petco’s selection of books on Brackish Water Fish and the variety of Petco Brand products available for the care and happiness of your new pet. All Petco Brand products carry a 100% money-back guarantee.

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

Pregnant women, children under the age of 5 and people with weakened immune systems should contact their physician before purchasing and/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.