The Biggest Aquarium Mistakes New Fish Keepers Make in 2026
Starting an aquarium can be an exciting and rewarding journey, but it's not without its challenges, especially for first-time fish keepers. If you're just starting out in 2026, you're not alone—many people are diving into the world of fish keeping. However, there are some common mistakes that even the most well-intentioned beginners make. As an experienced aquarium keeper, I want to help you avoid these mistakes, so you can enjoy a thriving, healthy aquarium with happy fish.
At School of Scape, we focus on guiding fish keepers at every stage of their journey, helping you build the confidence and knowledge needed to maintain a healthy and beautiful aquarium with ease. With the right guidance and the right products all in one place, avoiding common mistakes becomes much simpler. Let us walk you through the most common aquarium mistakes and show you how to prevent them.
Setting Up an Aquarium Without Proper Research
One of the biggest mistakes new fish keepers make is setting up their aquarium without doing enough research. Whether it's choosing the wrong tank size, picking incompatible fish, or failing to understand the equipment needed, skipping this important step can lead to a lot of frustration and even fish loss.
Why This Happens:
New fish keepers are often excited to set up their aquarium and rush into the process. It’s tempting to buy a tank, add water, and introduce fish without fully understanding what’s required for long-term success.
How to Fix It:
Before setting up your aquarium, take the time to learn about the needs of the fish you plan to keep. Research the appropriate tank size, filtration system, and water parameters for your chosen species. School of Scape offers helpful resources to guide you through this process, so you can avoid common mistakes right from the start.
Skipping Water Treatment and Why It Harms Fish
Water treatment is crucial in ensuring your fish thrive in their new environment. Many beginners make the mistake of thinking tap water is just fine for their aquarium, but untreated tap water often contains harmful chemicals like chlorine and chloramine.
Why This Happens:
New fish keepers may not know that tap water contains chemicals that can be harmful to fish. It’s easy to overlook water treatment, especially when everything else feels so complicated.
How to Fix It:
Always use a water conditioner to treat your tap water before adding it to the aquarium. Water conditioners neutralise harmful chemicals, making it safe for your fish. It’s a simple step that will go a long way in protecting the health of your fish. Make this part of your routine each time you change the water.
Overfeeding Fish and Its Impact on Water Quality
Overfeeding is one of the most common mistakes new fish keepers make. It can be tempting to feed your fish more than they need, thinking they will enjoy it, but this often leads to problems.
Why This Happens:
Fish look hungry and may swim up to the surface when they see you, prompting you to feed them more. Beginners may also be unsure of how much food is actually needed, leading to excessive feeding.
How to Fix It:
Feed your fish only what they can consume in 2 to 3 minutes, once or twice a day. Remove any uneaten food from the tank to prevent it from decomposing. By controlling the amount of food, you can maintain a healthy tank and avoid water quality issues.
Overstocking the Aquarium
Overstocking is another common mistake that beginners often make. It’s easy to get excited and buy too many fish for your aquarium, but overcrowding can create problems that are hard to manage.
Why This Happens:
New fish keepers may not be aware of how much space their fish need or how quickly fish can grow. They may also feel pressured to fill the tank with as many fish as possible.
How to Fix It:
Check the recommended stocking levels for each species of fish. Make sure your tank can accommodate the fish’s full adult size and consider the needs of your fish in terms of space and territory. For example, while some fish like bettas can thrive in a small tank, others, like goldfish, need much more space to live comfortably.
Ignoring Water Parameters Like Ammonia, Nitrite, and pH
One of the most important aspects of aquarium care is monitoring the water parameters. New fish keepers often overlook testing the water, which can lead to dangerous situations for their fish.
Why This Happens:
Testing water parameters can seem daunting, and beginners may not understand the importance of things like ammonia, nitrite, and pH levels. Some may assume that as long as the water looks clear, it’s good to go.
How to Fix It:
Invest in a good water testing kit and check your water parameters regularly. Ammonia and nitrites should always be at zero, and pH levels should match the requirements of your fish species. Regular testing is a simple habit that will help you keep your aquarium in tip-top shape.
Poor Maintenance Habits
Regular maintenance is key to keeping your aquarium healthy, but many beginners fail to establish a solid maintenance routine.
Why This Happens:
The thought of cleaning an aquarium can be overwhelming, especially when you’re unsure what needs to be done and how often. As a result, maintenance tasks may get put off, leading to problems down the line.
How to Fix It:
Set up a regular cleaning schedule. Clean the substrate, change a portion of the water each week, and clean the filter monthly. Regular maintenance will prevent a lot of headaches down the road and ensure your fish live in a healthy environment.
Rushing the Aquarium Cycling Process
The aquarium cycling process is crucial for establishing a stable and healthy environment for your fish. However, many new fish keepers rush this process, which can cause problems.
Why This Happens:
When new fish owners are excited to add fish to their tank, they may be eager to skip the waiting period and add fish too soon. They may not realise that cycling is necessary to establish the beneficial bacteria that process waste and toxins.
How to Fix It:
Be patient and allow the aquarium to cycle properly before adding fish. This can take 4 to 6 weeks, but it’s worth the wait. Use test kits to monitor the cycling process and only introduce fish once the tank is fully cycled.
Not Understanding Fish Compatibility
Not all fish get along, and many beginners are unaware of the importance of choosing compatible species for their aquarium.
Why This Happens:
New fish keepers often select fish based on appearance or popularity without considering how well they will get along with others.
How to Fix It:
Research the compatibility of each fish species before adding them to your tank. Consider factors like temperament, size, and environmental needs. There are many helpful guides available at School of Scape to assist with this process.
Conclusion
Starting your aquarium journey can be a bit overwhelming, but avoiding these common mistakes will help you build a thriving, healthy tank. With patience, research, and a little guidance from trusted sources like School of Scape, you’ll be on your way to becoming a confident fish keeper in no time. Happy fish keeping!
