How to Introduce Newly Bought Fish into Your Aquarium

Clean the gravel, rocks, and decorations thoroughly. After purchasing your aquarium and accessories, you need to wash everything in warm water. Avoid using soap or detergent for cleaning the gravel, rocks, or decorations; simply use warm water. This ensures that no dust, bacteria, or toxins remain on these items.

• You can rinse the gravel by placing it in a sieve. Put the sieve over a plastic bin and pour water through it, stirring the gravel until the water runs clear. Repeat the process several times until the water is clean.
• Once everything is clean, place the accessories in the tank. Spread the gravel evenly at the bottom of the tank, arranging the rocks and decorations to provide hiding spots and areas for the fish to explore.

Fill one-third of the tank with room temperature water. Use a clean bucket to pour the water into the aquarium, placing a plate on the gravel's surface to prevent the gravel from being disturbed during the water flow.

• Once you've filled the tank one-third full, add a water conditioner or dechlorinator to remove chlorine from tap water. Chlorine is harmful to fish and can lead to illness or death.
• You may notice the water turning cloudy for the next two to three days. This is due to bacteria growing, and it will clear up naturally after that.

Connect the air pump. It's advisable to attach an air pump to the tank to ensure there is sufficient oxygen in the water. Connect the air tube from the pump to the air stone or bubbler in the tank.

• Consider using a one-way valve for the tank, a small valve placed outside the aquarium to secure the air tubing. The one-way valve allows you to position the air pump lower than the tank and acts as a barrier to prevent water from flowing backward during a power outage.

Plant artificial or live plants. Live plants are beneficial as they help oxygenate the water, but you can also add artificial plants to provide hiding spaces for the fish. You may also use plants to conceal equipment for aesthetic purposes.

• Keep live plants moist by wrapping them in damp newspaper until you're ready to plant them in the aquarium. Bury the plant roots beneath the gravel, leaving the tops exposed. You can also add aquatic plant fertilizer to help them thrive.

Set up water circulation with a filtration system. Water circulation in the aquarium helps balance ammonia and nitrite levels from fish waste, while beneficial bacteria consume these harmful chemicals. You should circulate the tank water for four to six weeks to maintain a stable biological environment. Doing this before adding fish will ensure a healthier and more adaptable environment for the new fish. You can purchase a filtration system at a pet store or online.

• During the first few weeks of circulation, you'll notice ammonia building up by the second or third week. Nitrites will begin to accumulate once ammonia levels drop to zero. By the sixth week, ammonia and nitrites will return to zero, and you'll see nitrates starting to build. Nitrates are less toxic than ammonia and nitrites, and you can manage nitrate levels through regular water maintenance.
• If you notice a positive ammonia or nitrite reading while the water is still circulating, you should continue the water circulation process before adding fish. Healthy tank water should show zero for both of these chemicals.

Test the water quality. Once the water has been properly circulated, it's important to check the water quality. You can purchase a water testing kit from a pet store or online.

• The water should have zero chlorine, and the pH level should match or be close to the pH of the water in the pet store where you bought your fish.

Transport the newly bought fish in a plastic bag. Most pet stores will place fish in clear plastic bags. Keep the fish in a dark place while transporting them home.

• Try to get the fish home as quickly as possible, as they need to be introduced into the aquarium as soon as possible after being placed in the bag. This reduces stress and helps them adjust to the new water more quickly. The fish may appear slightly faded after the journey, but don’t worry – this is normal, and their color will return once they are in the aquarium.

Turn off the aquarium lights. Reduce the light level or turn off the lights before adding the fish, as bright lighting can create a stressful environment for them. The aquarium should also have plenty of plants and rocks for hiding spots. These decorations will help ease the fish’s stress as they adjust to their new home.

Introduce two or more fish at a time. This ensures that the existing fish in the tank can gradually get used to the new members, preventing the newcomers from being bullied, as they will have others to socialize with. Introducing fish in groups of 2 to 4 at a time helps maintain the balance of the aquarium population.

• Always choose healthy, disease-free fish. Monitor the newcomers closely during the first few weeks to ensure they show no signs of illness or stress.
• Some people isolate new fish in quarantine for two weeks to ensure they are free from disease or infection. If you have the time and a separate tank, using it as a quarantine tank is a good option. If any illness is detected, you can treat the fish without affecting the main tank or its water environment.

Open the fish bag and place it in the tank for 15-20 minutes. Let the open bag float on the water’s surface to allow the fish to adjust to the tank's temperature.

• After 15-20 minutes, open the bag and use a clean bowl to scoop out an amount of water equal to the amount already in the bag. This will double the water in the bag, with 50% from the tank and 50% from the pet store. Be sure not to pour the water from the bag directly into the aquarium, as it could introduce bacteria into the tank.
• Let the bag float in the tank for another 15-20 minutes. You can seal the bag to prevent water from spilling out.

Remove the fish from the bag and introduce them to the aquarium. After 15-20 minutes, you can release the fish into the tank. Use a fishnet to gently take them from the bag and place them into the water.

• Monitor the fish for any signs of illness. If there were fish already in the tank, ensure they don't harass or attack the newcomers. Over time, with proper tank care, all the fish will coexist peacefully.

Prepare a quarantine tank. Quarantining new fish ensures they are healthy and prevents any diseases from entering your established tank. The quarantine tank should have a minimum capacity of 20-40 liters, with an old filter sponge from the main aquarium to introduce beneficial bacteria. The tank should also be equipped with a heater, light, and lid.

• If you're a dedicated fish enthusiast, you likely have a quarantine tank ready. Make sure it is cleaned thoroughly and set up properly before bringing home new fish.

Quarantine the new fish for two to three weeks. Once the quarantine tank is set up, place the new fish inside to allow them to adjust to the new water conditions.

• First, open the fish bag and let it float in the tank for 15-20 minutes. This gives the fish time to acclimate to the water.
• After 15-20 minutes, open the bag and use a clean bowl to add an equal amount of water from the tank to the water in the bag. The bag will contain a mix of 50% tank water and 50% store water. Avoid pouring the bag water directly into the tank to prevent introducing bacteria.
• Let the bag float for another 15-20 minutes. You can seal the bag to prevent spillage. After this period, gently scoop out the fish with a net and place them in the quarantine tank.
• Monitor the fish daily for any signs of illness or parasites. If they remain healthy after 2-3 weeks, you can transfer them to the main tank.

Change 25-30% of the water. A water change helps the new fish adapt to the nitrate levels in the tank and reduces stress. This step is crucial if you don’t regularly change the water in the main aquarium.

• Perform a water change by removing 25-30% of the tank's water and replacing it with dechlorinated water. Then, circulate the water through a filter to ensure the nitrate levels are balanced.

Feed the existing fish in the main tank. If there are already fish in the tank before introducing the new ones, it's a good idea to feed the established fish first. Well-fed fish are less likely to be aggressive toward the newcomers.

Rearrange the decorations in the tank. Move the rocks, plants, and hiding spots to new locations. Reorganizing the decorations before introducing new fish will distract the existing fish and alter the territories they’ve established in the tank. This will give the new fish a fair advantage and help them integrate without being isolated from the old fish.

Help the new fish acclimate to the main tank's water. After the new fish have been properly quarantined, you should repeat the acclimation process to introduce them to the main tank's water, just as you did when placing them in the quarantine tank. This will help the new fish adjust to the main tank water and settle into their new environment more easily.

• Place the fish in a bowl or bag filled with water from the quarantine tank. Let it float on the surface of the main tank for 15-20 minutes. Then, use a clean cup to gradually add water from the main tank into the bag. The bag will now contain 50% water from the main tank and 50% water from the quarantine tank.

Release the fish into the main tank. Keep the fish in the bag or bowl for another 15-20 minutes, and then gently net the fish and place them into the main tank.

• Monitor the new fish over the following weeks to ensure they are settling in well with the other fish and showing no signs of illness.