How to Start a Guppy Fish Tank?


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I wish I knew this information which I’m going to share with you, when I got my first guppy fish.

I had no idea on how to setup a fish tank and didn’t know how to care for guppies. I’ve learned a lot from my mistakes and from the fishkeeping books I’ve read.

In this article, I will teach you how to set up and start your first guppy aquarium. I will teach you the following:

  • Choosing tank size and supplies
  • Cycling your aquarium
  • Adding fish to your tank
  • Maintaining your tank

Choosing Aquarium for Guppy

Guppies are small fish; they will grow up to 1.5 inches in size. They don’t need much space to live, but still, need a minimum amount of water to be healthy.

You can purchase your aquarium as a kit or you can purchase a tank, filter, lights and heater separately.

For beginners, I recommend going with a minimum 10-gallon aquarium kit, which includes all the necessary supplies you need to get started. I recommend the Aqueon Starter kit (you can purchase it from Amazon). The kit includes a 10-gallon glass aquarium, a hood with LED lightning, hang on the back filter, heater, fish food, water conditioner, fish net and a thermometer.

You can keep your aquarium bare bottom, but I recommend adding 1-2 inches of gravel or some other substrate. Substrate will help keeping your water clean. The fish waste that is not picked up by the filter will be settled at the bottom, which later can be removed with gravel vacuuming.

Cycling Your Aquarium

Aquarium cycling, called the nitrogen cycle is essential on new aquariums. Most beginners skip the aquarium cycling process, because probably they have never heard about it. So they don’t know how important this step is.

Skipping the nitrogen cycle, you can kill all your beautiful fish, so please make sure you give your aquarium enough time, before you introduce fish.

The nitrogen cycle is the process of growing beneficial bacteria in your fish tank that will help eliminate the toxic ammonia and nitrites, which is produced by fish waste and decaying fish food.

Aquarium cycling will not happen overnight, so you have to be patient.

Steps on how to cycle your aquarium:

  • Fill your tank with tap water and use a dechlorinator (I use Prime by Seachem)
  • To speed up the cycling process you can add beneficial bacteria (I use Seachem Stability)
  • Turn on your filter and let it run 24/7
  • Let the water cycle through your filter for about 5 days
  • Change 50% of the water, add tap water, Prime and Stability
  • Cycle for another 5 days and perform another 50% water change (add Prime and Stability)
  • Do this once again after another 5 days
  • Now you can introduce your guppy fish
  • Monitor the ammonia level in your fish tank
  • Do frequent water changes in the next two months
  • After two months, your aquarium should be fully cycled

The cycling process takes minimum two weeks, and you should avoid adding fish in this period.

Ammonia is a highly toxic compound. A small amount of ammonia in your water can kill all your fish. This is why you should always keep ammonia levels at 0ppm. To test ammonia, nitrite and nitrate levels, you can use an API test kit.

Adding Guppies to Your Aquarium

Once your aquarium is cycled, you can go to your local fish store and purchase some beautiful guppy fish. As I mentioned before, the complete nitrogen cycle takes a long time, up to 2 months.

Now that you have cycled your tank, it is time to add fish. But how many guppies can you add in your aquarium? An over-crowded fish tank might look good, but it is really bad for the inhabitants.

In fishkeeping, there is a very common rule to determine how many fish you can place in an aquarium. This is called the “one inch of fish per gallon” rule. Following this rule, an adult guppy will need 1.5 gallons of water.

The following list will help you determine the number of fish you can add in different tanks:

  • 10 gallons – 7 guppy fish
  • 15 gallons – 10 guppy fish
  • 20 gallons – 13 guppy fish
  • 25 gallons – 17 guppy fish
  • 30 gallons – 20 guppy fish
  • 35 gallons – 23 guppy fish
  • 40 gallons – 27 guppy fish

Although I do not recommend it, you can increase the number of fish you add in your tank. Filtration is the key. Adding a powerful, external canister filter with good filter media will help to keep your tank stable. For some of my bigger aquariums, I use Fluval external filter. These are the best in my opinion.

Maintaining Your Fish Tank

To keep your guppies healthy, it is important to maintain your tank regularly.

Once a week you should change 20-30% of the water (after it is cycled). For smaller aquariums, I recommend (5-10 gallon) 50% water change weekly.

Never do complete water changes, because you will kill all your beneficial bacteria, resulting in high ammonia level and fish death. Chlorine is as toxic for fish as ammonia. Always add dechlorinator to your tap water, before adding it to your tank.

Clean the glass of your tank with a sponge or cleaning brush. Use the sponge only in your fish tank! Algae are harder to remove from the glass. For this you can use an algae scrubber or magnetic algae cleaner.

Clean your filter every other week. Always keep and wash the filter media in aquarium water. Do not wash it in the siphon, because tap water, which contains chlorine and chloramine, will destroy all the beneficial bacteria in the filter media. Do not let the filter media dry out.

If you have live plants in your tank, remove the dying leaves. Decaying leaves are also contributing in raising ammonia levels in the water.

Once a month clean the substrate with a gravel vacuum. This will help remove the fish waste that is settled in the substrate.

Wrapping It Up

There you have it! Now you know how to select a fish tank, how to cycle and how to maintain it. Setting up a guppy fish tank is easy if you know how to do it.

Do not rush it! This hobby requires patience.


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Updated: September 15, 2021
Questions & Answers
  1. Ciro Riccardi

    Hi Fabian, I’m new at this, and find your advice very helpful. I love guppies, and will have about 4-5 males, and 1 Male betta with some neon cardinals, platys etc. All fish that you say can live with the guppies. Can any shark live with my community, esp guppies? I have a 20 gallon tank with plants and places to hide. Any advice you can give me will be very helpful. Thank you, Ciro PS Im following all your advice in setting up my tank, even equipment you recommend.

    1. avatar

      Hey Riccardi! I would not keep any type of sharks with guppies. Please keep in mind, that most sharks are aggressive (even the red tail shark – which many people think are peaceful). On top of that, sharks will grow to a large size, and will quickly outgrow your 20 gallon aquarium.
      Also, if you put a male betta with your guppies, choose one, which is less aggressive.

  2. hi I was wondering if you know if a guppy could be blind. my one guppy has been acting really weird lately. she is bumping in the the wall and hitting the other guppies in the face or butt. I also have a older male betta with them. the guppy will hit the betta really hard when the guppy swims up to get food. I am really hope that the betta doesn’t get mad at the guppy and kill him.

    1. avatar

      It is possible that guppy goes blind. Usually an infection or bacteria can cause blindness in guppies. I don’t think the betta fish is a big problem, but how the bling guppy will feed. Will do some more research on how to treat bling guppies and will update my guppy diseases page very soon.

  3. hi I was wondering if you know if a male betta will try to kill male guppies. I was thinking there tail is also really pretty and long. I was going to put male guppies with the betta but then thought what will happen will he try to eat them. my betta isn’t at all aggressive and he is a little lazy.

  4. Monica Knox

    I just read this a week after starting my first tank. I have a ton of problems- do you have any articles about fixing problems that were listed here… I didn’t cycle my tank. I also have an awful ratio of males:females (4:1) in a 5.5 gallon tank + 3 Neon Tetras, yikes! I’m thinking that I just need to get a larger tank. How urgent is this? and what can I do to correct/make the water safer?

    1. avatar

      In a 5.5 gallon tank I would not put more than 5 guppies after the tank is fully cycled.
      You can add beneficial bacteria to speed up the cycling process and hope that you will not lose fish.
      Do frequent water changes of 20-30%. You can do this on daily basis, until the tank get established.
      Also, you can bring back the fish you don’t need to the store. Usually, if the fish are still healthy, the store will accept it back.

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