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FISH / new pets

A Set-up Guide for New Algae Eater Fish

Tips for home and health


6 things to know about algae eaters

  • Types of algae eaters: otocinclus, hi fin, bristlenose, rubber lip and plecostomus
  • Experience Level: Beginner
  • Size: They grow from 2 inches to 2 feet (5-60 cm) long, depending on the species
  • Lifespan: They can live between 5 and 10 years (plecostomus can live 10 to 15)
  • Behavior: They should live with fish of similar size in a semi-aggressive aquarium; otocinclus, rubber lip and bristlenose can live in community tanks; pleco can live in aggressive tanks as well
  • Did You Know: They’re living “vacuum cleaners” that snack on aquarium algae

How do I set up my algae eater’s aquarium?

Set up the aquarium at least 1 day before you add any fish.

Aquarium & stand

  • The minimum size of an appropriate aquarium depends on how many fish you have and how big they will be as adults. Fish 6 inches (15 cm) long or under need at least a 20-gallon tank. The largest algae eaters need at least a 75-gallon tank.
  • The aquarium should be near a power source in a low-traffic area, away from direct sunlight and drafts.
  • Water weighs 8 pounds per gallon. Pick a very sturdy, stable base for your aquarium, then fill the tank with water.
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What do I put in the aquarium?

  • If you will be using an under-gravel filter, add it first.
  • Layer about 3 inches (8 cm) of gravel on the bottom of the tank (about 1½ pounds of gravel per gallon of water). Rinse the gravel before putting it in the aquarium.
  • Fill the tank about halfway up with dechlorinated water.
  • Add the thermometer and other necessary equipment.
  • Time to decorate! Add fish furniture, plants, rocks and other objects. Rinse all décor with dechlorinated water before adding it to the tank.
  • Finish by filling the tank the rest of the way with dechlorinated water.
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  • An aquarium filter should be able to process all of the water in the tank 3 to 5 times an hour. For example, the filter in a 20-gallon tank would need to push through at least 60 gallons of water each hour. Follow the manufacturer’s instructions to choose and set up the filter.
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Heat & light

  • Check the temperature your algae eaters require before you put them in your aquarium.
  • Choose an aquarium heater with 5 watts of power for each gallon of water in the aquarium. A large aquarium may require a heater at either end.
  • Wait 15 minutes after filling the tank before turning on the heater.
  • Place the heater close enough to the filter to distribute the warmed water.
  • Run the tank’s filter and hood light for 24 hours, then check the water temperature and adjust the heater if necessary.
  • Tropical fish require water temperatures of between 73 and 82 degrees Fahrenheit (23 to 28 Celsius).
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How do I add an algae eater to my aquarium?

  • Bring your algae eater home right away.
  • Place the algae eater, still inside the bag, in the aquarium. Let the bagged fish acclimate to the new water temperature for 15 minutes.
  • Next, use a net to transfer the algae eaters into your aquarium. Try not to transfer too much of the old water into the tank.
  • Add no more than 3 algae eaters at a time to make sure the filter can handle all the new action in the neighborhood.
  • The chemical balance in your aquarium will change with every new fish you introduce, so check the tank’s pH, ammonia, nitrite and nitrate levels regularly.
  • PetSmart stores offer free water testing.
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What do algae eaters eat?

Algae eaters move along the sides and bottom of the aquarium scraping off algae with their sucker mouths. They can also feed on commercial pelleted food. Choose spirulina pellets or algae discs of the appropriate size. Feed your new pet algae eater wafers daily along with occasional supplements of fresh veggies, like sliced zucchini or kale.

How can I keep my algae eater healthy?

If your algae eater displays any of these symptoms of illness or distress, talk to a PetSmart store associate or a veterinarian familiar with fish health:

  • Decreased appetite
  • Fins clamped to the sides
  • Scraping body on rocks ("flashing")
  • Abdominal swelling
  • Inflamed or discolored skin or fins
  • Unusual swimming pattern
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FREE water quality testing

PetSmart offers free aquarium water testing. Bring in a sample and we can test its quality within minutes.


  • Thoroughly wash and rinse your hands before contact with your aquarium.
  • Always add a dechlorinator or water conditioner to tap water before adding it to the aquarium. Do not use soaps or detergents to clean aquarium or décor, since they are toxic to fish.
  • Fish and aquatic animals can transmit disease to humans. Wash your hands with soap and water after interacting with your pet, the aquarium or aquarium water. Children, pregnant women, elderly people and people with immune-system problems should take extra care. Adults should assist children with hand washing.
  • Keep fish away from food and areas where food is prepared.
  • Never release fish into the wild.


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