How to Take Care of Aquarium Fish

How to Take Care of Aquarium Fish
Taking Care of Aquarium Fish

Taking care of aquarium fish involves creating a suitable environment, maintaining water quality, and ensuring the well-being of the fish. Here are some general guidelines to help you care for your freshwater aquarium fish:

Fish Tank Setup

Aquarium fish care starts with a proper fish tank setup.

Equipment and Supplies

Here are the equipment and supplies needed for a basic fish tank setup:

  • Tank: Choose an appropriate-sized tank based on the type and number of fish you plan to keep. A larger tank is generally more stable and forgiving.
  • Filter: Select a good quality filter that suits the size of your tank. Filters help maintain water quality by removing debris and providing a surface for beneficial bacteria to grow.
  • Heater: If you are keeping tropical fish, a heater is essential to maintain a stable water temperature. Most tropical fish prefer temperatures between 75-80°F (24-27°C).
  • Lighting: Provide appropriate lighting for your aquarium. Some fish and plants may have specific lighting requirements. Aim for a balance between day and night by using a timer for your lights.
  • Substrate: Use a substrate at the bottom of the tank. Gravel is a popular choice, and it comes in various colors and sizes. Make sure to rinse it thoroughly before adding it to the tank.
  • Decorations: Decorate your tank with ornaments, rocks, and plants. Ensure that the decorations are suitable for the type of fish you plan to keep and do not have any sharp edges.
  • Water Conditioner: Use a water conditioner to remove chlorine and other harmful chemicals from tap water before adding it to the tank.
  • Testing Kit: Invest in a water testing kit to monitor parameters such as pH, ammonia, nitrite, and nitrate levels. Regular testing helps ensure a healthy environment for your fish.

Setup Steps

Here’s are the steps involved in setting up a fish tank:

  1. Rinse the Substrate: Rinse the substrate thoroughly to remove dust and debris. Add it to the bottom of the tank, creating a layer of 1-2 inches.
  2. Install Equipment: Place the filter and heater in the tank according to the manufacturer’s instructions. Ensure that the filter is running properly before adding fish.
  3. Add Decorations: Arrange decorations, rocks, and plants in a way that provides hiding places and swim-through spaces for your fish.
  4. Fill the Tank: Fill the tank with conditioned water. Use a bowl or plate to disperse the water gently to avoid disturbing the substrate and decorations.
  5. Cycle the Tank: Allow the tank to cycle before adding fish. This process establishes beneficial bacteria that help break down ammonia and nitrites. Cycling can take a few weeks.
  6. Introduce Fish: Once the tank is cycled and water parameters are stable, introduce fish gradually. Avoid overstocking and monitor the fish for any signs of stress or illness.


Feeding your aquarium fish is a crucial aspect of their care, contributing to their overall health and well-being. Here’s a breakdown of key considerations for feeding your fish:

Choosing the Right Food

There’s a lot of different types of fish food, so it’s important to understand what’s available and what’s the most suitable for your fish.

Species-Specific Diet: Different fish species have varied dietary requirements. Research the specific needs of your fish to ensure you provide an appropriate diet. Some fish are herbivores, others are omnivores, and some are carnivores. Choose a food that aligns with your fish’s natural diet.

Commercial Fish Food: High-quality commercial fish foods are formulated to meet the nutritional needs of various fish species. Pellets, flakes, and granules are common types of commercial fish food. Consider the size of your fish and choose a suitable food form.

Supplementary Foods: In addition to commercial fish food, consider supplementing their diet with live or frozen foods like brine shrimp, bloodworms, or daphnia to provide additional nutrients. Some omnivorous and herbivorous fish may enjoy fresh fruits and vegetables such as cucumbers, zucchini, spinach, and peas.

Feeding Amount

For the optimal health of the fish, it’s important to understand how much to feed your fish.

Avoid Overfeeding: Overfeeding is a common issue in aquariums and can lead to poor water quality, obesity, and health problems for your fish. Follow guidelines provided on the fish food packaging and adjust based on the specific needs of your fish.

Observation: Pay attention to how much your fish consumes within a few minutes. Remove any uneaten food to prevent it from decomposing and affecting water quality.

Frequency: Establish a feeding routine based on the needs of your fish species. Some fish may require multiple small feedings throughout the day, while others may thrive on a once-a-day feeding schedule.

Feeding Schedule

Having a feeding schedule will help ensure the fish are fed properly.

Consistency: Maintain a consistent feeding schedule to provide a sense of routine for your fish. Consistency helps in regulating their metabolism and digestion.

Morning or Evening Feeding: Some aquarists prefer feeding in the morning, allowing fish to metabolize during the day. Others prefer evening feeding to simulate a natural foraging behavior. Choose a time that suits your schedule and the habits of your fish.

Fasting Days: Consider incorporating fasting days into the feeding schedule. Skipping a day of feeding once a week can help prevent overfeeding and mimic natural feeding patterns in the wild. Remember that individual fish may have unique dietary needs, and adjustments may be necessary based on factors like age, health, and environmental conditions. In general, juvenile fish require smaller more frequent feedings, while mature fish can handle larger less frequent feedings. Regularly assess the health and behavior of your fish to ensure they are receiving adequate nutrition.



Maintenance is an important aspect of aquarium fish care. Regular maintenance will ensure proper water quality, prevent diseases, and promote natural behavior of fish by reducing stress.

Establish a consistent maintenance schedule. The frequency may vary based on the size of the tank, the number of fish, and the type of filtration system. Adjust the maintenance frequency based on the specific needs of your aquarium.

Here are some things to consider regarding the maintenance of your fish tank:

Water Changes

In general, it is recommended to change 10-20% of the water in the fish tank on a weekly basis. With that said, the optimal volume of water to change and the frequency will be different depending on each fish and fish tank setup. These water changes will help keep proper water parameters (pH, ammonia, nitrite, nitrate).

Cleaning Fish Tank

The fish tank should be cleaned as part of the maintenance.

Substrate Cleaning: Gently vacuum the substrate to remove uneaten food and debris. Since you will be removing water from the tank during this process, you can also perform the water change during this process. This is a great example of “killing two birds with one stone.”

Algae Removal: Use an algae scraper or pad to remove algae from the glass and other hardscape in the tank.

Cleaning and Changing Filter

Aquarium filters should be cleaned and the filter media should be changed as needed. This will ensure the filtration system remains efficient and effective.

Mechanical Filtration: Mechanical filtration media should be changed as needed, especially if it starts to show signs of it getting clogged. A clogged mechanical filtration will reduce the water flow, which will impact the efficiency of the entire filtration system.

Chemical Filtration: If chemical filtration media (activated carbon, ion exchange resins) is being used, replace them according to the manufacturer’s recommendations to maintain their effectiveness.

Biological Filtration: Since the biological filtration media houses the beneficial bacteria, do not replace it unless it is necessary. If the biological filtration media appears to be clogged, simply rinse them gently with aquarium water to remove the excess debris. Tap water should be avoided, since it could kill the beneficial bacteria. If the biological filtration media ever needs to be replaced, replacing it in multiple phases would be ideal. For example, replace only half of the filter media first. Then, a few weeks later, replace the remaining half of the filter media.  


Monitoring your fish tank is an important part of aquarium fish care. By observation, you will be able to understand the needs of the fish.

Monitoring Water Parameters

Regularly testing and maintaining proper water parameters is essential for the well-being of your aquarium inhabitants.

Key parameters include:

  • Temperature: Use a reliable thermometer to ensure the water temperature remains within the appropriate range for your fish species.
  • pH Levels: Test and adjust the pH levels to match the requirements of your specific fish. Fluctuations can stress fish and impact their health.
  • Ammonia, Nitrite, and Nitrate Levels: Regularly test for these compounds to ensure a stable and healthy nitrogen cycle. Elevated levels can be harmful to fish.

Monitoring Equipment

Here are some basic things to monitor in regards to your equipment:

  • Filter System: Regularly check and clean the filter media to maintain optimal filtration. Ensure the filter is functioning properly to remove impurities from the water.
  • Heater and Thermometer: Confirm the accuracy of your heater and thermometer to prevent sudden temperature fluctuations.
  • Aeration and Oxygenation: Check air pumps and airstones to ensure proper oxygenation levels. Inadequate oxygen can stress fish and lead to health issues.

Monitoring Fish Behavior

Observing your fish’s behavior can provide valuable insights into their well-being:

  • Feeding Habits: Monitor feeding patterns. A sudden loss of appetite or changes in eating behavior may indicate health issues.
  • Swimming Patterns: Abnormal swimming, such as lethargy or erratic movements, can be a sign of stress or disease.
  • Social Interactions: Pay attention to interactions between fish. Aggression or isolation may indicate problems within the tank.

Preventing Disease

Here are some good practices in disease prevention:

  • Quarantine New Additions: Isolate new fish in a separate quarantine tank before introducing them to the main aquarium to prevent the spread of diseases.
  • Proper Cleaning Practices: Regularly clean and vacuum the substrate, remove uneaten food, and perform partial water changes to maintain water quality.
  • Avoid Overcrowding: Ensure the tank is not overpopulated, as overcrowding can lead to stress and increased susceptibility to diseases.

Identifying Early Signs of Disease

Early signs of disease include the following:

  • Changes in Color: Pale or discolored patches on the skin or fins can indicate illness.
  • Abnormal Growth: Look for unusual growths, lesions, or swelling on the fish’s body.
  • Erratic Behavior: Scratching against objects, rapid gill movement, or hiding can be signs of distress.

Treating Disease

Here are some good practices in treating disease:

  • Isolation: Remove the affected fish to a quarantine tank to prevent the spread of disease.
  • Medication: Consult with a vet or aquarium expert to choose the appropriate medication for the specific ailment.
  • Follow Treatment Instructions: Administer medication as directed, and monitor the quarantined fish closely for signs of improvement.

Seek Professional Advice as Needed

If you’re uncertain about a fish’s condition or if diseases persist, seek advice from a qualified aquarium professional, such as a vet specializing in fish health or an experienced aquarium hobbyist. Professional guidance can be crucial in addressing complex issues and ensuring the well-being of your aquatic pets.

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