A Step by Step Guide To Building A Colorful Aquarium

There is nothing like relaxing and enjoying the sight of a vibrant aquarium, the colorful patterns of fish erasing the stress of a hard day. Whether you’re interested in breeding your fish or just want the stress-relief of owning a lively fish tank, a lot of planning and preparation goes into setting up a freshwater aquarium. If you follow these steps – and have a little patience – you can be the proud owner of a colorful freshwater aquarium.

Planted aquarium with neon tetras
Planted Neon Tetra Tank (Flickr: Angelo Juan Ramos)

Step One: Planning

Before you rush out to buy anything, some planning is in order. Consider where you want to place your tank. You want to make sure you can see and enjoy it (after all, you’re going to put in a lot of work). The tank needs to be away from direct sunlight to prevent a battle with algae blooms. You want to avoid vents, especially if they blow down (you don’t want dust in your tank). The drafts can also wreak havoc on the temperature of your tank which will stress your fish.

Make sure the location is near an electrical outlet. You’re going to have to plug in equipment, and you don’t want to stretch cords. Also think about the distance from your closest water faucet. You’re going to make regular water changes – how far do you want to carry buckets?

Betta in a countertop tank
Betta in a countertop tank (Unsplash: Sarah Brown)

If you rent, make sure you’re allowed to have aquariums and verify the size limit. Remember, water is heavy: a gallon is around 8 pounds. That means a 20-gallon tank will weigh close to 170 pounds, and a 75-gallon aquarium can top 630 pounds! Make sure the floor can support the weight.

This is also a good time to consider the stand for your aquarium. An ideal stand will not only support the tank’s weight, it will have cabinets to hold all of your chemicals, cleaning supplies, fish food, and any extra aquarium needs.

Step Two: Supplies

Now that you have your plan in mind, it’s time to make your supply list. The basics should include:

  • Tank
  • Stand
  • Hood
  • Filter
  • Heater
  • Thermometer
  • Air pump
  • Substrate
  • Decorations
  • Background material
  • Test kits
Freshwater aquarium supplies
Complete set of freshwater aquarium supplies (Flickr: Joe Green)

Tank size selection depends on a few factors. As silly as it sounds, larger tanks are better for novice aquarists than smaller tanks – they’re easier to cycle and more “forgiving” of mistakes. Wide aquariums provide more swimming room. If you choose territorial fish (like cichlids) they also provide more “home turf” for the fish to defend. If you go with less active fish (gouramis or angelfish) then a taller, narrower tank is acceptable.

Consider the fish you plan to have, as well as how large they get. There is a standard rule of 1 inch (2.5cm) of fish per gallon, but remember that you won’t have an empty tank. For instance, a 10-gallon tank turns into an 8-gallon tank once it has plants and decorations in it – that means only 8 one-inch fish (at adult size!), not the 10 you might have anticipated.

Goldfish in a bowl
Always think of your tank size when selecting fish (Dreamstine: Sergey Khakimullin)

Hoods come with lights attached, or you can select glass covers and get separate lights. You’ll want a cover to prevent your fish from jumping, keep dust out of your tank, and keep children/pets from dipping into the aquarium (yes, it happens – just check YouTube).

Filters come in two varieties: power filters and under-gravel filters. If you’re a novice, a power filter is your best bet. You need to make sure you purchase a filter strong enough to circulate the size of your aquarium 5 or more times per hour (so if you have a 10-gallon tank, the filter should circulate 50gph). If you choose an under-gravel filter, you need to be prepared to regularly vacuum the substrate to prevent the filter from getting clogged.

The best heaters are submersible and have a dial you can set to the desired temperature. Just as important will be a thermometer – this serves as a check to make sure your heater is functioning properly.

An air pump isn’t necessary, but it dissolves oxygen into the aquarium which you’ll need for proper cycling (see Step Five). Just make sure to get a check valve – this keeps water from backing up into the tubing when you unplug the pump or if there’s a power failure.

Goldfish with gravel
Goldfish on colored gravel (Flicker – halfalive – so zzzzz)

Substrate choice depends on a couple of questions: Will you have live plants that require a specific type? Do you want more color options for your tank? Did you choose an under-gravel filter? You need 1-2 pounds of substrate per gallon of tank (i.e., a 20-gallon tank needs 20-40 pounds of substrate). Some of your substrate options include:

  • Gravel
  • Fluorite
  • Aquasoil
  • Clay/laterite
  • Soil/Peat moss mixture (You can make this yourself)

Decorations can be realistic or fantastic – it depends on the look you want for your aquarium. Consider placing live plants in your freshwater aquarium to enhance the visual appeal, provide shelter for your fish, and help with the cycling of the tank. Some plants need to be attached to decorations rather than being planted in the substrate, so make sure to read up on their requirements. Great plants for freshwater tanks include:

  • Java moss
  • Amazon sword
  • Hornwort
  • Anubias
  • Java fern
  • Dwarf water lettuce
  • Pygmy chain sword
Tropical planted tank
Tropical tank planted with Amazon sword (Flickr: Pete Brown)

Apart from adding color to your tank (or setting off the color of your fish if you opt for dark colors), background material helps disguise the cords and hoses coming off your equipment. Backgrounds easily attach with tape or Velcro.

You will need to test the water quality in your freshwater tank regularly, so a test kit is a must. If you notice problems with your fish, it’s also a good idea to check the water values first for changes. Make sure to read the instructions in your kit so you’re familiar with how to use it.

Freshwater test kit
API Freshwater Test Kit (Flickr, Rosemarie Bennet)

Step Three: Cleaning

Before you start, make sure everything is clean. Whatever cleaning equipment you use on the tank should be dedicated to your freshwater aquarium so you don’t risk contaminating your fish.

If you bought a brand-new tank, wipe it down with a damp cloth to remove the dust.  If you purchased a used tank, remove any visible debris, then wipe it down with vinegar and paper towels. If it’s an acrylic tank be very careful as it’s easy to scratch!

Once the aquarium is clean, you want to leak-check it (better now than when it’s full). Fill it with a couple inches of water and let it sit for an hour before running your finger along the bottom. If you feel any water, use an aquarium sealant to make repairs.

Whether you selected sand or gravel, it’s important to rinse the substrate thoroughly before use. A colander and high-pressure hose work best. Watch for the rinse water to run clear. Depending on the size of your substrate, it may not – just try to get the worst of the dust off. Decorations should undergo the same rinsing process. Live plants need to stay damp at all times.

If you selected a power filter, gently clean the filter material under the tap. If your style of filter uses a carbon packet, be careful not to rip it open.

Step Four: Set-Up

With your tank on its stand, you’re now ready to set up your freshwater aquarium!

With all of your equipment, make sure you read the included manual and instructions thoroughly before you start – it’ll save you hassle down the road.

If you selected an under-gravel filter, install it, connecting the pump’s airlines and powerhead.

Carefully add a thin layer of your chosen substrate, watching that you don’t scratch the bottom. Once you have the first layer down, add the rest. Think about where you want to add plants, decorations, and contour the bottom. It’s common practice to slope substrate down towards the front of the tank.

Simple decorated tank
Simple decorated tank with contoured subtrate (Flickr, Moto “Club4AB Miwa”

Add in your plants and other decorations. If you chose plants that need attachment versus planting, use fishing line to anchor them (sounds crazy, but it won’t hurt the plant or your fish).

Place a clean plate on the bottom and pour the water onto the plate – this keeps the substrate from moving. Even though you checked for leaks before, only fill the tank about 2-3 inches and do another leak check just to be sure (again, you don’t want to find a problem when it’s full!). Once you’re in the clear – and you’re sure everything is where you want it – fill the tank the rest of the way.

Fill the reservoir of your power filter and start it up. It should be quiet and start to circulate water. If you went with the under-gravel filter, switch on the powerhead and pump – you should see vertical movement of water in the lift tube.

Attach the heater near the expelling water of the filter. This makes sure the water gets evenly heated throughout the tank. Attach the thermometer on the opposite side of the tank as your check. Set the heater to your anticipated temperature (a good range is 78-82F/28-32C) and give it a couple of hours before checking the thermometer. The heater shouldn’t be turned on until the aquarium is full of water – it can overheat, and the glass may shatter when it hits the colder water!

Tap water conditioner
API Tap Water Conditioner (Flickr, Mattiel7)

Add a dechlorinator to neutralize the unwanted chemicals found in tap water, following the instructions on your bottle. You may need to remove the carbon filter in your power filter to prevent it from clearing the dechlorinator before it has a chance to work.

Step Five: Cycle the Tank

Unhappily, it’s not quite time to add the fish. Instead comes a period of waiting – called cycling – that turns your freshwater aquarium into a healthy environment.

This is where your test kit comes in handy as you watch for a spike in ammonia, nitrites, and nitrates, followed by a fall to 0ppm – that’s when you can start to introduce fish. If you add fish before the nitrogen cycle has a chance to finish, the fish end up exposed to those toxins, and they may not survive.

During this period, the water in your aquarium will get cloudy – this is normal. If you went with live plants, they’ll help with the cycling as will the air pump. Doing a 15% water change of the tank each day also moves things along.

Plants cycling an aquarium
Plants cycling an aquarium (Flickr, David Hinchliffe)

Step Six: Add Fish

Three to six weeks later (yeah, sorry – it’ll be that long), you finally get to add those fish you researched! However, don’t rush to the store and buy the entire community at once; you want to introduce a couple of fish at a time (no more than 4 at a time). Adding too many fish at once will overthrow the nitrogen cycle you worked so hard on.

When planning your aquarium, it’s a good idea to choose a balance between centerpiece fish and community fish.

Centerpiece fish are the biggest and most beautiful fish. You only need 1 or 2 of these. If they’re aggressive (bettas and angelfish), they aren’t going to tolerate being in a communal tank. There are peaceful options, though, such as dwarf gouramis and dwarf cichlids.

Community fish tend to be docile, and they don’t mind being in mixed company. They tend to be on the small side and some prefer schools. Good examples include catfish, neon tetras, guppies, and blackskirts.

Be very slow and careful when introducing fish into your freshwater tank. Turn off the lights on your aquarium and dim the lights in the room. Keeping the fish in the bag from the store, float the bag in your tank for about 15 minutes to acclimate the temperature (after all, the fish just went on a – hopefully short – car ride). You’re now going to introduce your new fish to your freshwater aquarium’s biome:

  1. Wash your hands thoroughly.
  2. Add about 1/2 cup of the aquarium water to the bag, being careful not to let any of the bag water into your tank.
  3. Repeat this process every 5 minutes until the bag is full.
  4. Discard half of the bag’s water into a bucket or down the sink (don’t let it go into your aquarium!).
  5. Start the process over until the bag is full again.
  6. Using a net, carefully transfer the fish into your tank (don’t transfer any water).
  7. Discard the bag and water.

Observe your fish closely over the next couple of days. They may not eat for the first 24 hours, which is fine, but they should eat the following day. The fish should swim around, and it’s okay if they hides in the décor you provided. As each fish settles in and your tank continues to cycle, you can slowly add to your community over the next few weeks.

Completed tank setup
Completed Tank Setup (Flickr, Dorothy)


A lot of planning, preparation, and work goes into setting up a freshwater aquarium, but the result is a colorful display you can enjoy for years to come. Whether you go with gravel and a printed background, or sandy substrate and a black background that allows your fish’s colors to shine, there is no wrong way to decorate a tank. Careful research into tank size, fish requirements, plant types, and the nitrogen cycle will ensure that your dream of owning a beautiful freshwater aquarium is only a few weeks away.

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