If you want freshwater fish as aquarium pets, then you must know how to care for them. Keeping a tropical aquarium can be a rewarding experience. Freshwater fish tanks are inexpensive to set up and maintain, and there is plenty of fish available to add to your new aquarium.

Building a tiny ecosystem of animals and plants is nothing short of outstanding. Many people cannot stop after they purchase their first fish tank and their hobby quickly involves bigger aquariums, more aquariums, or both!

Unfortunately, this task can be quite tricky for many fish keepers. Knowing which fish to purchase, basic maintenance, how much and how often to feed your fish, among other details, is important for keeping your fish alive and healthy.

This article will give you some tips that, if followed, will greatly increase your chance of success as a new fish keeper.

Condition the aquarium water

How to Take Care of Tropical Fish
How to Take Care of Tropical Fish

Water for fish is like air for humans. That’s something decisive to their long-term health. Tap water has countless properties that need to be balanced in an aquarium to support aquatic life. To properly condition water, use a de-chlorinating and biological aquarium supplement available at your local pet store.

It is highly recommended to check the water parameters of both the tank and replacement water. Most tap water (city water) contains either chlorine or chloramine. Using a water conditioner will neutralize chlorine in both cases, but ammonia will still be present in the latter. It has to be broken down by the nitrifying bacteria found in the aquarium. This may take longer than what your fish can tolerate.

Filtered water must also be checked regularly and it should be considered part of your aquarium maintenance routine. The filter membranes could be damaged or may require replacement prior to the expiration date.

Testing Aquarium Water

Water chemistry is not visible; it must be checked regularly. The best way to make this a routine is to check on the tank chemistry while changing the water.

The vital parameters are pH, nitrates, nitrites and carbonate hardness.

Stability is the main factor in pH. PH in the range of 6.5 – 7.5 is suitable for most species, but they can adjust themselves if it happens to be slightly out of range.

KH (carbonate hardness) is the indicator of pH stability. It should be kept under close observation if it comes close to 4.5 dH (degree hardness) or 80 ppm. You must take action if it drops below that.

Nitrites must be undetectable at all times (except during cycling). If nitrites are detected, make sure you check on ammonia as well. Nitrates should be kept below 10 ppm.

Maintain proper pH Levels

Condition the aquarium water
Condition the aquarium water

PH measures the acidity or alkalinity of your tank water. Purchase a pH test kit and use it to check the pH level. Freshwater fish thrive when the pH level is between 6.6 and 7.8, depending on the species. This range will offer a natural, antiseptic effect which helps your fish fight illnesses. If you want a healthy aquarium, check regularly to detect any fluctuations in pH levels.

Replace aquarium water

It’s recommended to change 25 percent of your aquarium water at least once a month. Smaller and more frequent changes are best for the health of your fish. If it is possible to change 10% – 15% every 15 days is best.

This will help maintain a clean and healthy tank, while also keeping nitrate concentrations at a safe level. Use a gravel vacuum to siphon out water and debris. Keeping your water clean and maintaining stable water parameters helps promote healthy and strong fish.

Maintain an adequate water temperature

Temperature changes can be harmful to aquarium fish. Don’t place your aquarium in a window that gets plenty of sunlight or next to heating or air conditioning vents, since abrupt temperature changes can make your fish sick or even kill them.

Tropical freshwater fish require a constant temperature of 70º – 85º F depending on the species, in which case you’ll need to purchase an aquatic heater for your tank.

Clean the sides of the tank

Not everything green is good. Algae buildup on tanks cloud the glass, makes the water cloudy and depletes oxygen, which can be harmful to your aquatic life. Thriving aquarium plants can also be harmed by the presence of algae.

If left unchecked, algae will rob plants of much-needed oxygen. Pet stores have several tools to help, which include scrub brushes, some with long handles and aquarium algae magnets to scrape off excess algae from the aquarium.

Aquarium plants are also very important

You need to care for freshwater aquarium plants too because live plants are capable of removing nitrates from the water, improving its quality and reducing algae growth. They also increase oxygen levels in the aquarium and provide good hiding spots for the fish.

It’s not only about aesthetics, since plants are helpful when it comes to establishing a natural ecosystem. They produce oxygen and, at the same time, they absorb carbon dioxide and nitrates, which is helpful to keep your aquarium clean and healthy.

Acclimate your fish

Fish are fragile animals. For best results, ask the store clerk the water parameters for nitrate, nitrite, ammonia and pH levels. At home, test the aquarium chemistry. The greater the differences, the longer you need to acclimate your fish.

Add your fish

Add your fish
Add your fish

Float the sealed bag with the fish in your aquarium for at least 15 minutes, but no longer than one hour, to allow for temperature acclimation. Open the bag and slowly add a quarter cup of water from your aquarium. Repeat the process of adding a quarter cup of water every five minutes until the bag is full.

This allows the temperature and chemistry to come together, which acclimates the fish in their new aquatic home, without having them shocked by sudden changes. Remove the bag from the aquarium and slowly pour off as much water as possible without putting your aquatic life in danger. Lower the bag into the aquarium again and allow your fish to swim out into their new home.

Give them space to swim

Overcrowding can cause oxygen levels in the water to drop. Overcrowding may also cause excess waste, which clogs the filter and degrades the aquarium water. On top of that, too many fish in small areas can kill them. Check with a pet specialist what is the right size tank for your fish.

Avoid Overfeeding Your Fish

Don’t worry, a fish seldom starves. One feeding per day is enough, making sure you provide food items for each type of fish in your tank.

Good flake food is enough in most cases but, if you have many bottom feeders, it’s a good idea to include sinking pellets. Don’s assume catfish and other scavengers will get what they need from flakes that float to the bottom of the tank. If you have algae-eating fish in your tank, you must include algae wafers to supplement their diets.

Don’t feed your fish with more than what they can eat in a few minutes. Excess food is not only unhealthy for the fish and prone to disease, but it clogs the tank and can cause spikes in the aforementioned chemicals. It can also cause unwanted situations, like excess algae growth or an outbreak of pest snails.

Many fish keepers put their fish on a feed/fast schedule, during which the fish are not for one or two days. This helps to keep the tank cleaner and the fish healthier. Simply put, remember that what goes into a fish must come out, so the more you feed your fish the dirtier the tank will get.

Recommended Aquarium Maintenance Routine


Make sure the equipment is working properly.

Watch your fish during feeding. Behavioral changes are a good indicator of a potential issue.


Count your fish. When a fish dies, smaller species can decompose quickly, resulting in ammonia and nitrite spikes, and eventually high nitrate levels.

Every Other Week

Recommended Aquarium Maintenance Routine
Recommended Aquarium Maintenance Routine

Test your water for the vital parameters: pH, carbonate hardness, nitrite and nitrate.

Change 10-15% of the water.

Vacuum the gravel. Clean the aquarium walls. Filter floss is fairly inexpensive and quite efficient. Start from the bottom and wash them frequently.

Rinse filter inserts (cartridges) with the extracted water.


Replace filter inserts, cartridges, floss and carbon.

Inspect tubing, connections, air stones, skimmers and other parts for proper operation.

Clean the aquarium top to make sure the lighting is not affected.

Check the expiration dates printed on the boxes and bottles of the aquarium supplies you use. Don’t use after the imprinted date. Expired test kits will give false readings and may prompt unnecessary measures.

With a healthy and well-managed tropical fish tank, you will have many happy hours of pleasure watching your fish swim in their aquatic habitat.