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How long does it take for a Tropical Fish Tank to Cycle

The fish keeping hobby is one that has greatly evolved; combining biological science with artistic creativity. More often than not, the type of aquarium you keep is determined by the kind of fish you keep in it. This means that if your fish are freshwater fish or saltwater fish, your aquarium will be freshwater or saltwater respectively.

A common flawed assumption is that those are the only two categories of aquariums in the hobby. While you may refer to them as the two most popular categories, other types of aquariums exist, one of which is the tropical aquarium.

For example, saltwater fish are known for their inability to survive outside their saline habitats; hence, the need to ensure that you fill your fish tank with compatible water for such fish. Tropical fish are like that—they can not survive in cold water. Therefore, by way of definition, a tropical aquarium is an aquarium that shelters tropical fish.

Overview of Tropical Fish Tank

As earlier stated, tropical fish naturally live in warm water and as such, if you choose to have a tropical aquarium, water temperature is the most important distinctive feature you need to take note of. Tropical aquariums typically come with heaters to regulate water and make tropical fish feel safe and at home.

Cycling is an important procedure in setting up a new aquarium; be it freshwater, saltwater, or tropical. Fish are perhaps one of the most sensitive aquatic animals there are, and bringing them into a replicated version of their natural habitat demands extreme patience and caution. Before adding fish to your new rank, certain chemical activities have to be ongoing to ensure the smooth and seamless adaptation of your fish to their new home.

The last thing you want is your fish becoming lethargic after being introduced to your new aquarium, or worse, dying. What then is cycling and what effects does it have on the survival of your fish and the successful setup of your tropical aquarium?

This article will answer these questions and provide helpful tips to complete the cycle. Before getting to the crux of the matter, allow us to give brief background information about tropical fish, the nitrogen cycle, and the relationship between these two and your tropical fish tank.

What are Tropical Fish

These are a species of fish that live in warm water; usually between 75 to 80 degrees Fahrenheit. The relationship between tropical fish, freshwater, and saltwater is that a tropical fish can wither a freshwater fish or saltwater fish.

The line of distinction here is that the fish in this category cannot survive extreme water temperatures and tropical waters are located close to the equator in the form of oceans and lakes. Tropical aquariums are a popular trend in the hobby.

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Tropical fish are typically small to medium-sized and come in diverse, beautiful shapes, bright colors, and bold patterns. These aesthetic qualities make them great for your aquarium. A vast variety of tropical fish species exist and a few examples are clownfish, bettas, rainbow sharks, orange butterflyfish, angelfish, catfish, guppies, tetras, red swordtails, mollies, black ghost knife fish, etc.

Tropical fish aquariums are the best for beginner aquarists because not only are they relatively inexpensive to purchase, but they are also easy to nurture. Note that if you decide to house tropical fish in your aquarium, they eat in small quantities compared to other types of fish; be careful not to overfeed them.

Setting up Tropical Fish Aquarium

Before cycling your tank, a few factors need to be considered; the location, size, and quantity of fish to be put in your new tank will influence the cycling process. Therefore, you need to set the right conditions for cycling to be a success.


Situate your tank on a flat, solid surface. Depending on the size of your tank, you may need a supporting structure such as a stand (mostly for tanks of about 40 gallons or more). Avoid slant surfaces as this will make your tank look bent and affect your fish and other elements in your aquarium.

For tropical aquariums, ensure that your tank is located close to an electrical socket; you will be needing heaters and filtration devices for your tank, this makes it easier to connect them to their power source. Avoid using extension cables to minimize all that wirework. The use of extension cords may cause trip and fall, or knock over accidents.

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Setting up your tank in a corner of the room may be the best way to avoid these Furthermore, tropical fish are highly sensitive to sound; do not keep your tropical aquarium near the television or speakers or in a generally noisy environment. The vibrations from these sounds will prove lethal for your fish. To prevent this, locate your aquarium in a cool, quiet place. Also, ensure that your aquarium is out of the reach of children and household pets.

Light condition

Tropical aquariums need to be kept away from direct sunlight during and after cycling. While lighting is necessary for aquatic plants to grow, it is important to strike a balance to avoid algae bloom. We recommend the use of artificial lights in your tanks as you can control the intensity and they also beautify your aquarium.

Water temperature

It was easier stated that the distinctive feature of tropical fish is their inability to survive in extreme water climates; they only live in warm water. To make your aquarium an ideal home for tropical fish, your water temperature is probably the most important factor you need to consider.

Tank cycling is useless if the fish die as soon as they are put in the aquarium. That is why tropical aquarium tanks must have heaters and thermometers. We recommend the use of submersible heaters because they come with thermometers attached to them and are often more accurate.

When planning your aquarium, ensure the heater is located in a place where it easily accesses all of the water and keeps the temperature at equilibrium. Heaters come in different ranges and as a guide; you will need 5 watts per gallon of water.


Water filters are important in any kind of aquarium because they keep your water safe from alien pollution. It also keeps beneficial bacteria in place, which is important to your cycling process. Ensure you purchase only original water filters for your tropical aquarium

Cycling your Tropical Fish Tank

The cycling process is one that must not be skipped while creating your aquarium. Even after following the aforementioned guidelines, your fish are still in danger if you do not cycle your tank properly or at all.

Cycling refers to the process during which you allow beneficial bacteria to develop and establish in your tank to stabilize your water chemistry and make your aquarium habitable for fish. There is a bit of science to this, but the summary is that in their natural habitat, a certain amount of bacteria are present.

So if your aquarium seeks to replicate the natural habitat that your fish comes from, it is important that bacteria are present in your water. To establish a bacterial colony in your tropical fish tank, there are many ways to do it:


This refers to bringing in beneficial bacteria from an old tank to your new tank; an ‘old’ tank refers to a tank that has already been established. You are taking elements from an established tank, that contain the beneficial bacteria, and putting them in your new tank so that they can establish there, it’s like sharing.

To seed your new tank, you can take gravel, filter media, driftwood, plants, and even water from the established tank into yours. These are carriers of beneficial bacteria and will successfully introduce them to your new tank. Before you seed from any tank, be sure that the tank is in good condition; do NOT seed from diseased tanks!


If you do not have a healthy established tank to seed from; or any established tank at all around you, you can start the nitrogen cycle on your own! We highly recommend this as your best option because you are free from any risks that come with seeding.

To cycle your tropical fish tank successfully, you need to well understand the nitrogen cycle and how long it lasts for. The nitrogen cycle is in three stages: the first stage is the build-up of ammonia.

Ammonia is created by the accumulation of fish waste, excess food, and decomposing dead fish or plants. In essence, all the garbage in your fish tank becomes ammonia and it is very toxic for fish. The second stage is the breakdown of ammonia into nitrites by beneficial bacteria known as Nitrosomonas. - For all your creative needs!

Nitrites; although less toxic than ammonia, are still very lethal to your tropical fish. Therefore, another group of beneficial bacteria known as Nitrobacter further break down the nitrites into nitrates. Nitrates are relatively harmless but need to be kept in check.

The entirety of these processes, from the build-up of ammonia to the end product; nitrates, is the nitrogen cycle. As this process requires the presence of beneficial bacteria, it is important to allow it before adding fish to your aquarium. Not only are bacteria useful during the nitrogen cycle, but they are also needed to keep nitrate levels in control.

As a tropical aquarium hobbyist, patience is essential in the setup of your fish tank. It is mandatory to allow the cycling process to complete before adding any fish. Do NOT add fish to your new tank before or during cycling as water chemical swings will affect them.

Cycle Period for a Tropical Fish Tank

How long does it take for a Tropical Fish Tank to Cycle?

Having understood the nitrogen cycle, the beginner aquarist may wonder how long it typically takes for cycling to complete. While the length of cycling may be influenced by different factors, cycling usually takes one month at LEAST.

Do you see why you need plenty of patience?

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Stage – 1

Duration Period (1-2 WEEKS)

This stage involves incorporating ammonia into your new tank; this is done by adding fish waste or uneaten food to your new tank. The ammonia build-up can be hastened by adding one or two starters tropical fish and feeding them moderately.

When ammonia begins to develop, the Nitrosomonas bacteria that will eat it start to form too. When ammonia is successfully introduced to your tropical fish rank and bacterial colonies begin to develop, the first stage is complete.

Stage – 2

Duration Period (1-2 WEEKS)

This is the stage at which ammonia is broken down into nitrites by the established colony of Nitrosomonas bacteria. Using original home testing kits, monitor the ammonia level and if it is rising too high, take out the starter fish and change your water partially to avoid over tasking the bacteria present in your tank and subsequently harming the fish. When the ammonia level peaks and begins to decline, the second stage is complete. You will notice a surge in nitrite levels; the beginning of the final stage.

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Stage – 3

Duration Period (1-WEEK)

This stage is the breakdown of nitrites to nitrates by Nitrobacter bacteria; and the end of the nitrogen cycle. Once the nitrate levels decrease, nitrate levels increase and that is a bit more relaxing. However, ensure that nitrate levels are kept below 20ppm.

If nitrates rise above this, you must change your water partially to curb the quantity of nitrate in your tank. Once the ammonia and nitrite levels in your tropical aquarium read 0ppm and the nitrate levels are well below 20ppm, your cycling process is complete.


Cycling your tropical fish tank is very important in creating a safe environment for your fish. Although we predict a month for the process to complete, it may take up to twice that period in some cases and that is normal.

What is very vital is that you let each stage of the process to complete before adding your fish. That is why we recommend that you buy your fish AFTER the cycling process. The aquarist hobby requires a lot of patience, monitoring, and maintenance which is eventually very rewarding. Research extensively on your choice of tropical fish before purchasing them.

Finally, ensure your home testing kits are purchased from a trusted supplier so that they give you accurate readings and results during the cycling process, and don’t forget that your tropical aquarium water needs to be at the right temperature at all times!