How to Fix a Betta Fish Tank (with Pictures)

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How to Fix a Betta Fish Tank (with Pictures)
How to Fix a Betta Fish Tank (with Pictures)

Because betta fish survive in a variety of environments, many people believe they can be left in decorative pots and tiny aquariums. In fact, they need a lot of space and filtered water to live well; When preparing your aquarium, always take into account the health and happiness of the goldfish. Also remember the top rule when it comes to betta fish: never leave two males in the same tank, or they will fight you until you bite.


Part 1 of 3: Choosing your aquarium and accessories

Set Up a Betta Tank Step 1

Step 1. Choose a suitable size aquarium for your fish

As much as you see betta fish in small plastic aquariums in stores, this is a species that needs more space to live well. If you want a happy and healthy fish, buy him an 18 liter or more clear acrylic or glass aquarium. Fish can jump, so the aquarium lid is important. With a properly sized tank, the fish will have plenty of room to swim and the water won't become contaminated as quickly.

  • It is possible to keep the fish in a small aquarium, but this requires weekly cleaning and water changes. If you want to put the fish in a small tank, choose one that is at least 10 liters; less than that will make the fish sick.
  • Betta fish should not live with each other. This is a rule for males that usually holds for females as well. The ideal is always to raise the betta fish separately, with their own aquarium for each one.
Set Up a Betta Tank Step 2

Step 2. Install a soft filter

Betta live in calm streams in the wild. Their long, flexible fins make it difficult to survive in heavy currents, so it's important to choose an adjustable filter to adapt the water's strength to your fish. When buying the filter, take into account the size and type of aquarium.

  • If you already have a filter at home and it is not adjustable, dampen the current with some plants. The recommended thing, however, is to buy a softer filter so as not to exhaust the fish by making them swim against the current.
  • Betta fish can survive in unfiltered water, but you need to clean your aquarium frequently to remove droppings and food debris. Leaving the tank dirty will not do the fish any good.
Set Up a Betta Tank Step 3

Step 3. Adjust the temperature of the aquarium

Betta fish are tropical and live best in water temperatures between 23 °C and 29 °C. If you live in a cold region, buy a water heater with a thermostat so you can control the temperature of the aquarium.

  • If you live in a region with a hot climate capable of keeping the water between the recommended temperatures, you don't need to use a heater. It is important that the water never drops below 23°C, however.
  • If you purchased an aquarium with less than 18 liters, using a heater can be dangerous and overheat the water. All the more reason to buy a suitable fish tank.
Set Up a Betta Tank Step 4

Step 4. Line the aquarium with gravel

Gravels are important to the aquarium's artificial ecosystem, as they store bacteria that help break down fish waste. Buy small gravels whenever possible, as waste and food scraps can get stuck on the larger rocks, damaging the aquarium's condition.

  • If you are going to put live plants in the aquarium, you will need at least 5 cm of gravel for the roots. If you are going to use artificial silk plants, 2.5 cm is more than enough.
  • Choose a blue, green or brown gravel. Lighter colors like pink and orange create a less natural environment for the fish.
Set Up a Betta Tank Step 5

Step 5. Place plants and other decorations in the aquarium

Living plants help to clean the water and create a natural environment for the fish. If you want to put real live plants in the aquarium, choose species that live well in the tank conditions, taking into account temperature, current and substrate.

  • Remember that for the plants to survive, the aquarium needs at least 5 cm of gravel depth. Using real plants creates a more natural ecosystem in the aquarium, adding more oxygen to the water and reusing the waste as fertilizer. For more information about plants, click here.
  • If you want to use artificial plants, buy silk models without sharp edges. The betta's fragile fins can be injured if they swim close to the plants.
  • Choose other decorations to keep the fish happy. Hiding places, such as caves and tunnels, are excellent options for the fish to feel safe in the aquarium. Never use sharp decorations or those with uneven surfaces that could catch the fish's fins. Use fine water sandpaper to smooth out trouble spots.

Part 2 of 3: Setting up the aquarium

Set Up a Betta Tank Step 6

Step 1. Place the aquarium in a safe place in the house

Choose a spot close to a window but not exposed to direct sunlight. Place the aquarium on a firm surface that will not tip over. If you have other animals at home, try to place the aquarium in a room that cannot be accessed by them.

  • It may be a good idea to purchase an aquarium support suitable to support the weight of your chosen tank.
  • To accommodate the filter and heater, leave at least 10 cm of space between the aquarium and the wall.
Set Up a Betta Tank Step 7

Step 2. Install the filter

Each type of filter has different installation instructions, so check your model's instruction manual to avoid problems.

  • If using an externally powered filter, install it at the back of the aquarium. Some aquariums come with lids with cutouts to facilitate this. Fill the aquarium before turning on the filter.
  • If you choose an underwater filter, place its plate first to check the fit of the tubes. Do not turn on the filter before filling the aquarium with water.
Set Up a Betta Tank Step 8

Step 3. Add the gravels

Wash the pebbles under cold running water to remove traces of dust that could clog the filter. Spread them over the aquarium, creating a layer up to 7.5 cm with a slant at the back of the aquarium. Place a clean dish on top of the gravel and start pouring water over it. The platter will prevent the movement of water from turning over the gravel. Continue to fill 1/3 of the aquarium.

  • As you add more water, check for possible leaks. When you find one, stop filling the tank and fix the problem.
  • Remove the dish after finishing filling the aquarium.
Set Up a Betta Tank Step 9

Step 4. Place plants and decorations

For live plants, bury the roots under the surface of the gravel and arrange them so that the shortest plants are in the front. This will give you a better view of the fish.

  • All decorations must be firmly attached to the gravel so that they do not come loose.
  • After filling the tank, avoid putting your hands in the water. Arrange everything before you finish filling the aquarium.
Set Up a Betta Tank Step 10

Step 5. Finish filling the aquarium and turn on the filter

Fill the aquarium completely, leaving only two fingers high between the water and the edge. Then turn on the filter and see if the water is circulating smoothly and quietly. Adapt the settings if the filter seems too strong.

Set Up a Betta Tank Step 11

Step 6. Install the heater inside the aquarium

Most heaters are fixed to the inside of the aquarium with suction cups. Place the heater near the filter outlet to heat the water evenly. Plug it in and install the thermostat to monitor the temperature.

  • Adjust the heater settings so that the water temperature is between 23 °C and 29 °C.
  • If installing lighting in the aquarium, turn on the light and see how it affects the temperature of the water. If it changes the temperature a lot, replace it before putting the fish in the aquarium.
Set Up a Betta Tank Step 12

Step 7. Add a neutralizer to the water

It is a substance that removes chlorine from the water needed when filling the aquarium with tap water. Check the product label to see the recommended amount for your tank size.

  • If you used distilled water, which does not contain chlorine, it is not necessary to add the neutralizer.
  • It's also a good idea to put a bacteria catalyst in the water to promote a healthy aquarium environment.
Set Up a Betta Tank Step 13

Step 8. Cycle the water before placing the fish

Cycling the aquarium without the fish helps build a beneficial population of bacteria. If you skip this step and put the fish straight into the aquarium, it may die of "shock". Click here to learn how to cycle and prepare the aquarium for the fish to arrive. You will need a test kit to monitor your water's ammonia, nitrate and pH levels.

  • The ideal pH is 7. The ammonia and nitrate levels must be 0 so that the fish can be placed in the aquarium.
  • You may need to use an ammonia remover to lower component levels.

Part 3 of 3: Placing the fish in the aquarium

Set Up a Betta Tank Step 14

Step 1. Buy a betta fish

The ideal is to leave to take the fish home only when the aquarium is ready to receive it. Thus, the transition of the animal to the new home will be faster and smoother. Go to a pet shop, pick a fish and take it home. Remember that each betta needs its own aquarium.

  • Look for a full-finned and colored betta.
  • If the fish appears to be floating aimlessly, it may be sick. Choose a fish that will swim with ease.
Set Up a Betta Tank Step 15

Step 2. Place the fish in the aquarium

Place the fish in the aquarium for an hour, bag and all. Keep the bag closed so that its water reaches the same temperature as the aquarium water. This way, you prevent the animal from suffering a shock when entering the aquarium. After an hour, open the bag and let the fish swim freely through the aquarium. From now on, the precautions are:

  • Feed the betta once a day. Only use betta foods.
  • Do not overfeed, or the aquarium will get dirty with debris and waste.
Set Up a Betta Tank Step 16

Step 3. Change water as needed

If you have installed a filter, you need to replace 20% of the water every week to keep the environment healthy. In the case of an aquarium without a filter, it is necessary to change 50% of the water to keep the environment clean for the fish. To change the water:

  • Prepare fresh water by filling a clean container the day before changing. Allow the water to reach room temperature overnight and add a conditioner if you are using tap water.
  • Transfer some of the old aquarium water to a clean container. Put the fish in the container.
  • Remove the necessary amount of water that needs changing, according to the size and type of aquarium.
  • Pour in fresh water. Add some fresh water also to the container where the fish is resting to get used to it.
  • After a few hours, return the fish to the aquarium.
Set Up a Betta Tank Step 17

Step 4. Clean the aquarium frequently

The cleaning method will depend on the type and size of the tank. With the use of the filter, cleaning can be done every two weeks; without using the filter, cleaning should be done once a week. Vacuum gravel to remove bits of food and waste. Clean the glass or acrylic sides and scrub any dirty decorations.

  • Cleaning can be done whenever you add more water to the aquarium. If you use a filter, you don't need to clean every time you add more water.
  • Use common sense to decide if the aquarium needs to be cleaned or not. If it looks dirty, clean it, even if you just did it.
  • Monitor water ammonia, nitrate and pH levels. Make the necessary changes to keep the environment healthy for the fish.


  • If you are going to put live plants in the aquarium, remember to consider lighting.
  • Buy a bacterial supplement to kill microorganisms harmful to fish.
  • As much as water conditioners are cheap in non-specialized stores, try to buy them in pet stores. Talk to the store professionals to choose a quality product that won't harm your fish.


  • Don't trust everything fish shop vendors say. Do your own research and talk to others on internet forums before making any decisions.
  • Don't put two male bettas in the same tank, or they'll fight to death. In some cases it is possible to put two females together, but doing so is not recommended either. Males tend to kill females they are not breeding with.
  • Do not put fish in a bowl or a vase. Such containers do not heat reliably, provide no filtration, and limit fish movement.

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