Master Small Marine Fish Care: Tank Setup, Food, & Compatibility Guide

This care sheet covers a variety of small marine fish species, including:

• Dwarf angelfish
• Damsels and chromis, depending on species
• Dottybacks
• Dartfish
• Gobies
• Blennies
• Reef-safe wrasse, depending on species
• Hawkfish, depending on species
• Dragonets
• Basslets, depending on species
• Cardinalfish
• Jawfish
• Clownfish, depending on species

Typical appearance and behavior

• Some species are solitary and territorial
• Tend to inhabit all levels of the aquarium
• Some species, like dwarf angels, may eat coral polyps and nip at clam mantles
• Some may form symbiotic relationships with other marine life such as shrimp, urchins or anemones
• They come in a vast array of colors and shapes
• Every species varies in personality, from shy and timid to active and bold
• Some small marine fish species exhibit behaviors such as jumping and burrowing

Characteristics

Habitat size

A minimum of 10+ gallons is recommended for smaller adult species; however, water conditions can change rapidly in smaller water volumes. A larger aquarium is recommended for schools of small marine fish species and species thatcan reach a moderate adult size.

Building your habitat

• Water health - Provide proper filtration to ensure optimal water quality to help maintain health. Slow to strong water circulation, based on species, should be provided to mimic water currents found in the small marine fish'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. The addition of a protein skimmer can aid with maintaining great water quality and high dissolved oxygen levels. An aquatic heater should be used to stabilize water temperature, ensuring it does not fluctuate more than 2 degrees in either direction in a 24-hour period. The specific gravity should remain stable. Do not allow specific gravity to fluctuate more than 0.001 in either direction in a 24-hour period
• Décor - Provide rock and décor for hiding places and plenty of room for movement
• Live rock can provide a natural food source while also enhancing biological filtration
• Some species of small marine fish are good jumpers; a secure cover is recommended to keep them safe
• Some species like to burrow and sift through substrate and will appreciate a smaller grain and softer substrate

Feeding

A well-balanced small marine fish diet consists of:

• Commercial algae sheets and wafers
• Flakes, pellets, frozen, freeze-dried and live foods

Things to remember when feeding your small marine fish:

• Feed small amounts 1 to 2 times daily, no more than fish will eat in 1 to 2 minutes; some species may need 2 to 3 feedings per day
• Some species require algae or algae sheets to be present at all times
• Thaw frozen food before feeding

Small marine fish care

• Water care: Maintaining great water quality with regular water changes and adequate filtration is important to help keep your small marine fish 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, which are a major cause of stress and disease

Where to buy small marine fish

Small marine fish 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.

Supplies

• appropriate size aquarium
• appropriate food, dry and frozen
• décor
• water conditioner
• aquarium salt
• filter
• water test kit
• full-spectrum lighting
• net
• thermometer
• protein skimmer
• marine substrate
• heater
• refractometer
  • cover
  • live rock

Tank mates

• Compatible tank mates will vary by species selected; please research individual species for compatibility. Depending on the species, two males may fight with one another and may not accept the addition of another of their own species, unless a mated pair
• Introduce new inhabitants to the aquarium gradually

Health

Signs of a healthy small marine fish

• 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
• Erratic swimming
• Labored breathing
• Weight loss
• Cloudy eyes or pop-eye
• Bloating
• Listlessness

Common marine fish health issues

FAQs

• What are the best beginner saltwater fish? Some great small marine fish species for the first-time marine aquarist are clownfish, chromis, damsels and dottybacks.
  

• Goby Care Sheet
• Reef-Safe wrasse Care Sheet
• Clownfish Care Sheet

Notes and resources

Ask a Pet Care Center partner 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 the Centers for Disease Control at cdc.gov/healthypets 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.