[The picture is from Petbarn,the copyright belongs to the original author]

Fishkeeping seems simple, but it needs some knowledge and skill. Beginners often make mistakes. These mistakes can hurt the fish and may even kill them.

Error 1: Using round or irregular-shaped fish tanks

Round or odd-shaped tanks cannot hold needed gear like filters and heaters. The water cannot move well. This makes bacteria grow, hurting the water and the fish. The tank shape can also hurt the fish's eyes. Use a normal rectangle or square tank instead. These tanks let you install filters and heaters properly.

Error 2: Using a fish tank without any of the following features (no filtration, no heating, no thermometer)

Beginners often forget basic tank gear like filters, heaters, and thermometers. The filter keeps water clean. The heater gives tropical fish the right warmth. The thermometer checks the water heat. A tank without these things cannot give fish what they need. This leads to sick or dead fish.
Error 3: Using decorative items such as colored stones, artificial aquatic plants, and coral.

Stores sell pretty colored stones and fake plants. But these often have bad chemicals like dyes and plastic. These chemicals get into the water and slowly poison the fish. Some cheap decorations can also cut a fish's skin and cause sickness. Use natural stones and plants instead. Do not use dyed or fake things.

Error 4: Lack of knowledge about fish behavior, resulting in hasty purchases and mixed breeding

Different fish have different habits. Some fish are very territorial and will attack smaller fish. If you do not learn about fish before buying them, they may fight and die. Before you get fish, research their water needs and how they act. Make sure you can give them a good home.

[The picture is from Everything Fishkeeping,the copyright belongs to the original author]

Error 5: Mixing tropical fish with cold-water fish

Tropical fish and cold-water fish need very different water heat. Putting them together causes stress and health problems. Tropical fish like water from 24 to 26 degrees Celsius. Cold-water fish like water from 16 to 18 degrees. Do not mix tropical and cold-water fish. Be careful mixing big and small fish too. Big fish might attack small ones.

Error 6: Excessive stocking density

Too many fish in a tank makes the oxygen in the water go down. Fish can die from not enough oxygen. To stop this, figure out the right number of fish for your tank size. A good rule is one liter of water for each centimeter of fish length. An air pump can add more oxygen. But with too many fish, even a pump may not keep them healthy.

Error 7: Directly using tap water to feed fish without proper treatment

Tap water has a lot of chlorine. Chlorine is poison for fish. Do not use tap water straight from the tap. You can put the water in the sun for one day. Or you can run an air pump in it for two days before it goes in the tank.

Error 8: New fish are directly placed in the fish tank without adapting to the water temperature

Beginners often skip the step for new fish. Putting new fish right in the tank can shock them. They might even die from the fast change in water and heat. The right way is to put the whole bag in the tank water. Let the water in the bag slowly mix with the tank water. This helps the fish get used to the new home.

Error 9: Purchasing sick fish

If you do not look closely, you might buy a sick fish. When you pick a fish, watch how it moves. See if it has cuts, strange marks, or torn fins. Healthy fish are active and quick. Do not pick fish with dull colors or slow movement.

Error 10: Misunderstanding of Water Plant Cultivation

Water plants are a key part of the tank. They need light and carbon dioxide to make food. Beginners often forget about light and plant food. A plant light helps water plants grow. Different plants need different light amounts. Plants also need to root in sand or gravel. Pick a good base like aquatic soil.

[The picture is from The Easy Aquarium,the copyright belongs to the original author]

How can beginners properly care for fish?

Build a fish tank

Tank size is important. A small tank uses less room. But a bigger tank is easier for a beginner. A bigger tank has more stable water, so fish get sick less. If you have the space, get a tank at least 60 centimeters long. It will be much simpler to manage.

Set up a filtration system

The filter is the "heart" of the tank. It takes dirt from the water and adds oxygen. Two common types are overhead filters and under-gravel filters.

The overhead filter is good for its price. But it uses a lot of space. Putting it next to the tank works well. If your home is small or you care about looks, this may not be best. The under-gravel filter looks neat and works powerfully. But it costs more and is hard to set up. For beginners on a budget, it can be too expensive.

Open the cylinder

First, wash the tank well inside and out. Do not use soap or scented cleaners. Just use clean water. For hard stains, use a little white vinegar to wipe them. Next, put in the bottom sand. Sand looks nice and helps with filtering. Use river sand or special tank sand. Put a thin layer on top and a thicker layer below. This looks better.

Then, add water. Do not pour it straight in or the sand will fly everywhere. Use a plastic bag. Pour the water onto the bag slowly. The sand will stay in place.

Install the filtration system

After you set up the filter, do not turn it on yet. Fill it with water and plug it in to let it run. You might see bubbles in the water. This is normal and will stop soon.

Water quality preparation

New tank water has bad stuff for fish, like ammonia. You can add nitrifying bacteria to break down these poisons. It takes about 7 to 10 days to get the water ready. Only put fish in when the water is stable.

Daily fish-keeping tips:

Temperature control

Fish are sensitive to water heat. Tropical fish like water around 25°C. If the temperature changes too much, fish get sick. Buy a heater to keep the temperature steady.

Frequency of water replacement

You need to change the water often. Change about one-third of the water each week. Use a tube to take out the dirty water from the bottom. Then add new water slowly.

Feeding techniques

Do not feed fish too much. Extra food makes the water dirty. Feed them one time each day. Give them only the amount they can eat in five minutes.

Other important points to note

Fish get sick sometimes. White spot disease is very common. If you see white spots on a fish, make the water warmer, to about 30°C. Use medicine made for this sickness. Follow the directions on the bottle. Green water means too much algae and bad water. Clean the tank well. Then change half the water and add an algae cleaner. The water will be clear again in a few days.

Raising fish looks simple, but it needs a lot of patience. From setting up the tank to keeping the water good, and then the daily feeding and care, every step must be done with care.