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11 Fishkeeping Mistakes Newbies Often Make




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Mistakes are a common part of learning anything new; fishkeeping is no different. While you can’t avoid all mistakes, we’d like to help you steer clear of some of the most recurrent mistakes.

1. Overstocking

Looking at the fantastic display of fish of all sizes and colors is lovely. But if you overpopulate them in any given space, it will come to a horrible end.

The fish won’t have enough room to grow. And wastes won’t clear completely from the tank. The unfortunate result will be sluggish, unhappy fish. 

Fish need enough room to thrive, so you’ll need to have an appropriate number of fish for the size of your tank.

You have to consider the volume of your tank, the surface area, and each fish’s characteristics. For example, some species are very aggressive)

2.Cleaning too much

Understandably, you would want to go out of your way to keep your fish tank and equipment clean. After all, it’s a tad expensive.

However, if you over clean, you interfere with good bacterial growth, which affects your fish.

While a certain amount of cleaning is necessary( weekly partial cleaning ), you shouldn’t overdo it. 

What’s more, avoid using detergents or any harsh cleaning agents; they only wreak havoc on your tank’s bacterial balance. 


It’s easy to think that all fish eat fish flakes, and that’s all there is to it. But that’s not necessarily true.

Fish eat, and sometimes prefer, different foods. Like all other animals, fish can be herbivores, omnivores, or carnivores.

feeding pet fish

You have to find out the type of food that your fish enjoy the most. 

You also have to be careful not to overfeed. Some fish will always look like they want more, even when they’re full, and then spit it out.

Apart from wasting food, all the excess will start to decompose and mess up the bacterial cycle in your tank.

In the same vein, don’t fall into the trap of underfeeding. Bottom line, feed your fish the right quantity of appropriate food.

4. Cleaning the filter with treated water

As a beginner fishkeeper, you’ve probably heard of the importance of filtration for your fish tank. So you try and keep your filter clean.

Unfortunately, you make the mistake of washing it under running tap water. 

The filter keeps the good bacteria that helps turn the fish waste into less harmful substances.

Now, if you wash it with treated tap water with germ-killing substances like chlorine, you kill off bacteria.

You end up with a horrible bacterial imbalance, and your fish won’t be able to deal with the waste. 

Instead of using treated water, you should clean your filter in a bowl using old tank water.

It’s not meant to be squeaky clean anyway; just wash off the excess goo. 

5. Not isolating new fish

When you get home from the shop with your new fish, you may want to put them into the tank right away. But that’s a big mistake.

adding new fish to an aquarium

Not only can the new fish harbor illnesses, but it may also not adjust well to the initial shock of the new company. 

Also, the new fish need to adjust after traveling from the shop.

So you have to put it in a separate tank or bowl for about a week or two while it settles. Only then can you introduce it to its new friends. 

6. Self-treating

Asking Google is quite helpful, but it’s not to replace the actual vet.

Sadly many people make the mistake of depending on google for diagnosing and treating their fish. This is very dangerous and can cause harm to the fish. 

It’s best to seek a consultation with a vet when you are unsure about anything to do with the fish’s health.

7. Lighting 

The lights make the tank look spectacular, but leaving them on for too long affects the fish.

On the flip side, not having any light will affect the natural balance of the tank. 

Beginners sometimes make the mistake of too little or too much light.

You need to switch off the light, especially at night, so your fish can sleep well.

fish keeping mistakes

8. Not including plants in the aquarium

Beginners may think plants will only add to maintenance work on the aquarium and leave them out altogether. That’s usually not a good idea.

For one, the best environment for fish is one that closely resembles the natural environment.

And secondly, plants help maintain balance. The plants assist in removing excessive nitrates, which can poison your plant. 

9. Inadequate research

Fishkeeping is an excellent therapeutic hobby, but if you become too enthusiastic and don’t do your proper research, you may get frustrated.

You need to study the types of fish, the right aquarium size, the full-grown length of the fish, compatibility, food, and many other factors.

You have to learn everything there is to know about your chosen fish breeds. 

10. Ignoring water quality


Newbie fishkeepers may overlook testing the water quality, including its PH. It’s essential to regularly test the water to know precisely how things are going in the tank.

Low water quality and the wrong pH may seriously affect the fish. Doing a water test once a week should be enough. 

11. Underestimating the cost

Fishkeeping will cost you quite a bit. On top of the setup costs, you’ll need regular maintenance to keep the fish thriving. 

Therefore, you have to be prepared to handle the expenses. One mistake newbies make is underestimating the costs and then running into problems later. 

To avoid this, have a clear picture of costs right from the beginning.

Check the prices of equipment, food, medicine, and anything else you need before committing to this hobby. 

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