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Setting Up A New Aquarium

Your guide to setting up your new aquarium

Getting Started | Filling Your Tank | Freshwater Acclimation | Saltwater Acclimation | Acclimating Invertebrates | Aquarium Maintenace | Socialization | Adding Plants

Updated on November 03, 2021
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Reviewed by Don Spaeth
Petco’s National Aquatic Care, Education and Programs Manager

An aquarium with a variety of different fish can be a beautiful addition to your home. Fish make wonderful, colorful pets and are relatively easy to care for as long as their pet parents are knowledgeable and diligent. With a little preparation, the right supplies and regular maintenance, your fish can live happy, healthy lives.

 

Getting started

Filling Your New Aquarium

After purchasing your new aquarium, make sure to set it up, add water, substrate and plants and allow it to settle for at least 24 - 48 hours before adding fish.

Once you’ve got your aquarium set up, you’ll be ready to choose which fish will populate your tank. Choosing the right type of water and fish will be the key to a harmonious aquarium. Remember, your tank is still cycling, while adding beneficial bacteria can help this process, it’s always wise to start off with a small number of fish and monitor your water chemistry to ensure your tank can properly keep up with your new bio-load. Consult a Petco aquatic specialist to find out more about the nitrogen cycle and what’s best for starting up your new aquarium, regarding adding aquatic life!

Types of Water

  • Freshwater: With less variables compared to a saltwater aquarium; this is a good place for new aquatic enthusiasts to get their feet wet! You don’t have to get a saltwater tank to have beautiful fish; with hundreds of different types of fish and colors, there is something for everyone!
  • Saltwater: Also known as marine or seawater, maintaining a saltwater tank tends to be more of a challenge as saltwater requires a lot more experience with water chemistry, patience and understanding. Before starting a saltwater tank, consult a Petco aquatic specialist with any questions you may have.

Varieties of Aquarium Life:

  • Coldwater Fish: Coldwater fish are generally thought to only be goldfish but there are plenty of other beautiful fish species, including some marine species, that appreciate a home in a cooler aquarium.
zebra danios
  • Tropical fish: Tropical fish, which include freshwater and saltwater species, are beautiful and come in many varieties, sizes and colors.
  • Brackish fish: Brackish water is a good way to gain an understanding of some of the extra detail that needs to be understood for a saltwater tank. There is a good amount of species that can live in freshwater and brackish water allowing the system to be a little more forgiving than a full saltwater aquarium would be. Consult your Petco aquatic specialist to learn more about brackish water fish and their needs.
  • Goldfish: A classic favorite, goldfish are a hardy bunch coming in many different shapes, sizes and colors. Be careful not to mix goldfish with tropical fish as the two varieties need very different environments.

Acclimating a New Fish to Your Freshwater Aquarium:

Items you’ll need to acclimate freshwater fish:

  • Scissors
  • Bucket
  • Watch or timer
  • Towel (for spills)

How long should I wait to add fish to a new freshwater tank?

You should wait between 24 and 48 hours before adding fish to your new freshwater tank. This will give your water time to reach the proper temperature and your other water parameters to reach their appropriate levels. Your aquarium will still be cycling for another few weeks, and the introduction of fish will help this along.

Adding Fish to a New Freshwater Tank (Steps)

We all know just how stressful moving can be, acclimation to a new tank can put physical and mental strain on new aquatic life. Follow these steps to ensure a healthy, stress-free transition for your freshwater aquatic life.

  1. Turn off any aquarium lights to reduce stress on your new aquatic life.
  2. Wash your hands thoroughly to prevent contaminating your tank’s water.
  3. Allow the sealed bag with your new aquatic life to float in your aquarium for at least 15 minutes but no longer than an hour. Make sure the water in the bag is the same temperature as your tank before moving on to the next step. (If the bag has torn or the water inside smells foul, do not pour any of the remaining water in the bag into your tank).
  4. After the temperature in your aquatic life’s bag has acclimated, carefully remove the rubber band or cut it open as close to the top as possible.
  5. Slowly pour out as much water as possible into a bucket without harming your aquatic life.
  6. Grasping the bottom corner, lower the bag into your aquarium.
  7. Lifting the bottom corner of the bag, let your new fish swim out of the bag.
  8. Be sure not to pour any remaining water in the bag into the tank.

Acclimating a New Fish to Your Saltwater Aquarium

Items you’ll need to acclimate saltwater fish:

  • Scissors
  • Bucket
  • Algae or lettuce clip
  • Refractometer
  • Measuring cup
  • Watch or timer
  • Towel (for spills)

How long should I wait to add fish to a new saltwater tank?

You’ll want to wait at least three days—ideally a week—before adding fish to your new saltwater tank. There are more water quality factors to consider than in a freshwater aquarium, which is why you should wait longer for the water to adjust. It’s recommended to initially add only a few fish to ensure the water is safe.

Adding Fish to a New Saltwater Tank (Steps)

Follow these steps to ensure a healthy, stress-free transition for your saltwater aquatic life.

  1. Turn off any aquarium lights to reduce stress on your new aquatic life.
  2. Wash your hands thoroughly to prevent contaminating your tank’s water.
  3. Allow the sealed bag with your new aquatic life to float in your aquarium for at least 15 minutes but no longer than an hour. Make sure the water in the bag is the same temperature as your tank before moving on to the next step. (If the bag has torn or the water inside smells foul, skip immediately to step 8).
  4. After the temperature in your aquatic life’s bag has acclimated, carefully remove the rubber band or cut it open as close to the top as possible. Fold the top edge of the bag down one inch to create an air pocket within the lip of the bag. This air pocket will allow the bag to float on the surface of the water. If possible, secure the bag to the side of your aquarium with an algae or lettuce clip.
  5. Test the specific gravity of your aquarium water as well as the specific gravity of the water in the bag to make sure they are close to matching
  6. Open the bag and slowly add aquarium water to the bag, using a quarter cup for small bags and half a cup for large bags. Close the bag again, then repeat every five minutes until the bag is filled. If there is more than a .004 difference in the specific gravity, double the amount of time between adding water to the bag.
  7. Once it is full, remove the bag from the aquarium and discard half of the water in the bag into a bucket. Be careful not to harm your aquatic life.
  8. Let the bag float again in the aquarium and repeat steps 6 and 7. This step allows further acclimation and will eliminate most of the original water in the bag.
  9. Once the bag is full, remove it from the aquarium and slowly pour out as much water as possible into a bucket without harming your aquatic life.
  10. Grasping the bottom corner, lower the bag into your aquarium.
  11. Lifting the bottom corner of the bag, let your new fish swim out of the bag. If you are introducing an invertebrate, submerse the bag and carefully remove the invertebrate. For corals, be careful to handle only by the base.
  12. Be sure not to pour any remaining water in the bag into the tank.

Important things to remember

  • Never rush the acclimation process. Following the steps patiently can even help revive aquatic life that appears listless or inactive.
  • Always let your fish swim out of the bag on their own. Trying to handle the fish with your hands or pouring them into a net may remove the protective slime coating making your fish vulnerable to disease.
  • Do not use an airstone in the bag when acclimating a new life to your tank. Airstones increase pH much too quickly and exposes aquatic life to lethal levels of ammonia.
  • Keep your aquarium lights off for several hours after introducing new aquatic life to reduce stress.

Acclimating invertebrates to your aquarium:

Stable water quality, temperature, pH levels and specific gravity of 1.020-1.025 are crucial to avoid severe stress and trauma to invertebrates and marine plants. If you are unsure of the water quality or pH levels of your tank, Petco provides free water testing.

Introducing coral to your aquarium:

After you’ve acclimated a new coral to your tank, you may need to remove excess slime that some  corals produce. Taking care not to touch the “flesh” part of a coral and using powder-free latex gloves, hold the coral by the rock or skeletal base and shake it gently in the shipping bag before placing in aquarium. It may take a few days for the coral to open after it has been introduced to your tank.

Maintaining a Flourishing Aquarium

Fish, like people, have very distinct personalities. As a pet parent, you’ll want to consider the different temperaments of your fish when introducing new species to your tank. Keep these tips in mind to make sure your aquarium is a happy, peaceful place.

  • When planning the amount of fish you want in your aquarium, a good general rule to follow is the 1” of fish per gallon ratio for freshwater tanks (with the exception of goldfish which should be 1” of fish per 5 gallons and 1” of fish per 3 gallons of water for saltwater tanks and take into account your fish’s adult size to avoid overcrowding or your fish outgrowing their environment.
  • Make sure that the species in your tank are compatible before introducing them to each other. Some fish just don’t get along.
  • Depending on the species and size of the fish in your aquarium, you may want to separate aggressive carnivores from other fish that are not the same size and temperament. You don’t want a new addition to wind up a snack for an old friend.
  • Different fish prefer specific areas in the aquarium. Some fish eat at the top while others prefer the mid-level of the tank and some choose to lay low at the bottom of the tank. Balance the levels to reduce competition for space.
  • Decorating the landscape inside your tank is not only fun, it provides hiding places and shelters for your fish to explore.

Socializing the New Guy

An aquarium can be like a playground. Sometimes the new kid on the block can have a hard time fitting in. If your new fish is being harassed by one of the older ones, try these options:

  • Feed your fish before introducing a new fish to the aquarium to alleviate any aggressive behavior.
  • Change or move decorations around to reduce territorial disputes.
  • Floating plastic holding tanks can confine aggressive fish for several hours while the new arrival adjusts to the new surroundings.

Adding Plant Life to Your Aquarium

Adding plants to your tank can really liven up your aquarium. Plants offer beautiful decoration and fun hiding places for your fish. However, just like other living things in your aquarium, plants need specific attention to thrive.

Plants to avoid:

  • Dead or dying plants: decomposing plants will affect the water quality in your aquarium.
  • Duckweed: although not hazardous, this floating aquatic plant tends to be a nuisance, blocking out light entering your tank. We would advise avoiding duckweed altogether but, if you do decide to introduce this plant, prune regularly.
  • Newly fallen branches: driftwood is a common addition to aquariums. However, branches that have fallen recently from trees may contain harmful resins or compounds.
  • Pine branches: this wood is dangerous for your aquarium and may be home to organisms you do not want entering your tank.

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