How to set up a New Fish Tank

How to set up a new fish tank

So, you decided the time is right to get into fish keeping and wonder how to set up a new fish tank. But you haven’t decided yet what type of fish tank you want or need. The fun thing about having aquariums is they are very unique and personalized. And you get to make something that you love.

Getting a new aquarium ready for fish can seem challenging, but it doesn’t have to be if you use this step-by-step guide. With some initial setup and patience, you can establish a healthy freshwater tank.

  • The key equipment you need to get started is the tank, filter, heater, etc.

  • How to prepare and cycle a new aquarium before adding fish.

  • Keep the proper ammonia, nitrite, and pH levels and what they should be.

  • When it’s safe to introduce hardy fish into the tank.

  • Ongoing care tips to maintain clean water and healthy fish.

  • How to fix new tank issues like cloudy water or too much algae.

When setting up a new aquarium, it’s important to learn some basic fish tank facts first. The general rule is to allow at least one inch of fish per gallon of water. This ensures you don’t overcrowd the tank or add too many fish together, which can cause issues.

Research what size your fish will grow to when it is adult. A healthy aquarium contains the right balance of fish, plants, lights, filters, etc.

Also, be aware of the type of fish you want to keep. Some fish really don’t get along, so you will want to choose good tank mates.

Choosing a location

When choosing a spot for your new fish tank, pick a stable, level surface away from direct sunlight and heating/cooling vents. Kitchens or family rooms often work well. Have an electrical outlet nearby to plug in equipment like the filter and heater. Make sure to keep the tank secure from curious pets.

Supplies Needed

There are some essential supplies you’ll need to get before you set up a new fish tank. First, purchase the tank and stand. Get an aquarium filter appropriate for the tank size. Choose a quality heater and thermometer. You’ll also need substrates like gravel, decor items, live plants if desired, a lid, an aquarium light, a water conditioner, and a water de-chlorinator. Test kits are used for monitoring water parameters. Have fish nets, tubing, and other tools on hand, too.

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Aquariums: Fish Tanks to Consider

Now, it is time to select an aquarium or fish tank. Standard rectangular glass tanks are the most common. Rimless open-top fish tanks can create a sleek look. Acrylic tanks are lightweight but scratch easier. Small desktop nano tanks are good for offices. Larger tanks allow more fish but require more maintenance. I also think larger tanks are easier to maintain. Plan your tank size based on the available space you have in your house and the types of fish you would like.

Aquarium Size

The size of your aquarium significantly impacts the type and number of fish you can keep. Bigger is often better, providing more stable water parameters. Bigger aquariums let you keep bigger fish like ocars, angelfish, goldfish, or even those cute little plecostomus fish you can buy in the pet store that grows to be a foot or longer. Allow at least 20 gallons for a beginner freshwater setup. Know your fish’s adult sizes and personalities- don’t overstock the tank or put aggressive fish with peaceful fish. Big fish in a small tank restricts swimming and promotes disease. Follow the one-inch of fish per gallon rule as a starting point.

Small tanks, under 5 gallons, are good for shrimp and snails, but not fish, while very large tanks are used for bigger fish.

I know you can find pretty beta fish stocked at any pet store, and they sell small tanks for them, but in reality, these fish need a proper tank, at least a 10-gallon, just like other fish. And goldfish also need a proper tank, not just a small bowl.


A reliable heater is crucial to maintain proper tropical fish tank water temperature between 75-82°F. Select a fully submersible heater sized for your tank – budget about 5 watts per gallon. Purchase an adjustable heater with a built-in thermostat. Test it for a few days before adding fish. The heater should turn off when the set temperature is reached. You don’t want to boil your fish. Place it near a filter outlet for circulation. Monitor water temperature with a separate thermometer.


A good filtration system is very important for your new aquarium. It is used to remove fish food and waste and provide biological filtration. Make sure you have the right size for the tank and type of fish. Cartridges need replacing monthly, and the media (the filtration sponges, rings, and other items you put in canister filters) need to be rinsed and cleaned regularly.

Here are a few different options to choose from:

  • Power filters that hang on the tank are very common. They are usually called ‘hang-on back filters. They usually have cartridges that water flows through.

  • Canister filters work well for large tanks. These use added filter media and are more customizable to your tank needs.

  • Undergravel filters are another option.

  • Internal filters are placed inside the aquarium.

Go above the minimum filtering recommendation for best results. Filters where you can control the flow of water are best in some tanks. Some fish like water currents to swim in, while others like to just be lazy and have a little water movement.


Proper aquarium lighting promotes fish health and plant growth. Most tank kits include an aquarium hood with built-in lights. If you are buying your equipment individually, choose an LED fixture for energy efficiency and customization. Full spectrum LED lights are best for a tank with live plants, or what is called a “planted tank.”

A quick look at lighting requirements:

  • Allow 6-8 hours of light daily. Timers automate the schedule. If you keep your lights on too long, your tank can develop algae and be much harder to clean. Pure sunlight can also encourage algae growth, which is why it is recommended not to keep your tank by a window.

  • Locate lights over sections needing more growth. Of course, this only works if you do not have a light hood.

  • Check and maintain lighting and electrical equipment regularly.


Choosing the right substrate and decorations enhances the aquarium’s aesthetic or look. It makes your tank look awesome, just like you want it to. None of the options are wrong; it just depends on what look you want. I currently have a 55-gallon tank with sand, a 10-gallon and a 3-gallon desk tank with soil, one 10-gallon with a mix of sand in the front and plants in soil in the back of the tank, and a large 75-gallon with gravel.

For tropical fish and tanks, small-grain aquarium gravel or sand works well. They can look very nice.

Some people choose not to have anything on the bottom of the tank because they are easier to keep clean.

Some planted tanks use specialized aquarium soil, called “aqua soil.”


Let’s talk decorations. The first thing to remember is you do not want too many. Arrange decor items thoughtfully, allowing an open swimming room. Rinse off all decorations well before adding them to your tank. You can always change and replace items for a different look.

Driftwood, rocks, caves, and live or artificial plants provide hiding and exploring areas. Some fish do much better if they have a place to get away and feel safe.

You can also make a themed tank with decorations specifically made for aquariums. These can be sold as kits at pet stores or online. I have tanks with just natural landscaping with rocks, living plants, and driftwood. I also have a tank with gravel, artificial plants, and a castle. It is fun to have different looks.

Other Aquarium Accessories

Some other accessories you will need include:

  • An aquarium thermometer to maintain proper water temperature

  • Water conditioner

  • A fishnet

  • Cleaning tools, like a siphon gravel cleaner and algae scraper

  • Test kits

Things to get later if you choose to wait, include:

  • An air pump with airline tubing and an air bubbler. This aerates the aquarium water, giving the fish the oxygen they need in the water.

  • You can get a drip acclimator for when you add new fish. This is a device to slowly add water to the plastic bag you brought your new pets home in to get them used to the water in your tank.

  • You will eventually want to have aquarium salt and medications on hand, just in case.

Just remember, purchase only essentials at first – add more later.

Fish Tank Shopping List

How much does it cost to set up a new fish tank?

The cost of a new aquarium setup varies greatly based on size, type of fish, and accessories. A small 5-10 gallon tank kit can run $50-100. Larger tanks cost hundreds more.

Fancy tropical and schooling fish are pricier than common varieties.

Allow $200-800+ for a full fish-keeping setup as a beginner, including the actual fish you want to keep.

Aquariums and equipment are sold separately, or you can make it easy on yourself and buy an all-in-one aquarium kit. It really just depends on the tank, fish, and look you are going for.

To save money, you could buy used tanks or equipment.

But make sure to invest in a quality setup to ensure healthy fish long-term.

How to set up a new fish tank

Start by cleaning the new aquarium extremely well before filling it. Use lukewarm tap water only – no soap. Rinse several times.

Place on a sturdy aquarium stand, away from direct sunlight.

Add substrate, decorations, and plants as desired.

Install filter, heater, and other equipment.

Finally, fill the tank with dechlorinated water and turn on the filter and heater.

A quick tip is when you fill your tank with water, you can put a small dish in the bottom to pour into so it doesn’t mess up your gravel or substrate. Another way to do it is to pour the water over the decorations or driftwood. But go slowly.

What type of fish should you keep?

There are different personalities with fish. Some are peaceful, some are aggressive.

When choosing fish, select hardy species appropriate for beginner community aquariums.

Good options include livebearers like platies, swords, and mollies which tolerate a range of water conditions.

Tetras, rasboras, and danios are active schooling fish that add movement.

Bottom dwellers like corydoras catfish and bristlenose plecos help clean up food. I personally like otocinclus fish or siamese algae eaters for my clean-up crew in my tank.

Bettas are popular but do not do well with aggressive fish.

Gouramis and guppies offer bright colors.

Do research to select fish that fit together based on size, water parameters, temperament and habitat. Start with just a few types initially.

How long do you have to wait to put fish in a new tank?

It’s important to wait 4-8 weeks before adding any pet fish to a new aquarium. The tank needs this period to establish beneficial bacteria and stabilize water parameters through the initial nitrogen cycle. Introducing fish to too many fish too soon exposes them to unsafe levels of ammonia and nitrite that can make fish sick or even kill them. Have patience when setting up a first tank.

Adding aquarium fish too soon

Adding fish to a tank that hasn’t cycled risks their health and safety.

Ammonia from fish waste accumulates quickly without enough beneficial bacteria to process it. High ammonia burns fish gills and poisons them.

Nitrite also prevents proper oxygen absorption.

Let the aquarium fully cycle first to make sure it’s fish-safe and healthy for inhabitants long-term. Don’t rush this critical step, or your fish could all die.

How the nitrogen cycle works (fish tank cycle)

The nitrogen cycle is all about water quality. It is the process of establishing essential nitrifying bacteria that remove toxic ammonia and nitrite from the water, producing safer water chemical levels.

It takes 4-8 weeks in a new tank.

Ammonia first converts to nitrite, then nitrate by growing bacteria colonies. Nitrate levels are reduced by partial water changes.

Test kits track progress cycling a tank.

Only add fish slowly once ammonia and nitrites show 0 ppm, and nitrates are under 40 ppm. This creates a healthy habitat. Otherwise, you can kill your new fish!

Testing the Water

After you set up a new fish tank, you need to test your aquarium water parameters frequently, especially in the first few weeks. Use test strips or liquid kits to check levels of pH, ammonia, nitrites, and nitrates.

Test weekly during cycling, then monthly or when issues arise. Collect water samples before changing out any water when levels peak. Ideal ranges are pH 6.5-7.5, ammonia 0 ppm, nitrites 0 ppm, and nitrates under 40 ppm. Match test results to room temperature water.

Stabilizing the Water Parameters

Regular partial water changes help stabilize the aquarium water parameters. Target 10-15% weekly.

Use a gravel vacuum to remove waste. Replace the water regularly with water that has been treated with water dechlorinator and that is at the same temperature as the water in your tank.

Add water conditioner as directed to detoxify tap water for fish. Activated carbon will help even out problem areas.

Increase the times you change the water if ammonia or nitrites rise. Reduce frequency once levels remain stable.

Consistent maintenance provides fish with a healthy, balanced environment.

Step by step

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  • Choose an appropriate-sized tank and sturdy aquarium stand. Allow 1 gallon per inch of adult fish.

  • Select the proper filtration system (power filter, canister filter, etc) rated for your tank size.

  • Purchase a quality adjustable submersible heater and thermometer. Heat water to 75-82°F.

  • Obtain decorations, substrates, and live plants if you are building a planted tank.

  • Thoroughly wash the tank with a damp cloth, equipment, gravel, and decor with water only—no soap.

  • Add the substrate like gravel or sand sloped higher in the back.

  • Place decor, plants, hides, wood, etc in the tank.

  • Install filter and heater per instructions. Position near water flow.

  • Fill the aquarium with dechlorinated tap water. Use the water conditioner as directed.

  • Allow your tank to cycle for 4-8 weeks, testing water parameters weekly.

  • Partially changing the water controls ammonia and nitrites and maintains stable water parameters.

  • Slowly introduce a few hardy fish once levels stabilize, then add more fish gradually.

  • Monitor pH, ammonia, nitrites, and nitrates using test kits.

  • Enjoy watching your fish thrive in their carefully cycled aquarium!

Planted Tanks
10-Gallon Aquarium

Ongoing Maintenance and Care

  • Caring for an established aquarium involves regular upkeep.

  • Feed fish once or twice daily, just enough food for most fish to finish in a few minutes.

  • Siphon the gravel and refresh part of your water weekly or biweekly.

  • Scrub algae off the glass as needed.

  • Rinse filter media monthly in old tank water. Replace filter cartridges per the manufacturer’s guidelines. Test water parameters monthly.

  • Remove decaying plant matter and tune up the tank decor when doing tank maintenance.

  • Observe fish daily for signs of stress or disease.

Tank Health/Troubleshooting

It’s important to monitor aquarium health and troubleshoot issues as they arise. Test water parameters regularly to catch problems early. Cloudy water, excessive algae growth, disease, or dying fish signal something is wrong. High nitrate over 40 ppm requires more frequent water changes. Rapid pH fluctuations stress fish. Treat diseases with proper medications if they persist. Identify and isolate sick fish in a quarantine tank. Reduce feeding if water pollution seems high. Overfeeding leads to excess waste and algae growth. Ensure equipment like filters are working properly. Make adjustments as needed until stability returns. A healthy tank starts with the initial cycle – maintain conditions through testing and care.


How many fish can I add to my tank?

Start buying fish with just a few hardy fish, then slowly add more over several weeks. Make sure only to add enough fish as your tank can safely hold to avoid overstocking.

What fish are best for a beginner aquarium?

Good starter fish include guppies, platies, mollies, bettas, rasboras, danios, corydoras, catfish, and bristlenose plecos. Avoid delicate species initially.

How often should I feed my fish?

Feed your fish small amounts 1-2 times per day. Only feed enough fish healthy enough that fish food they can consume in 2-3 minutes maximum. Overfeeding pollutes the water.

Why are my fish dying in a new tank?

High ammonia, nitrites, incorrectly cycled tank, poor water parameters, temperature shock, or disease may kill your fish. Make sure to fully cycle the tank before adding fish.

When should I change the filter cartridge?

Swap filter cartridges every 4-8 weeks as they accumulate debris. Rinse used cartridges in old tank water during your regular tank maintenance to extend usage.

How do I lower nitrate levels?

Nitrates accumulate from fish waste and excess food. Lower levels by performing regular partial water changes and removing decaying plant matter. Target under 40 ppm.

Why is the water cloudy?

Cloudy water is often caused by a bacterial bloom. It should clear up within 1-2 weeks as the tank cycles. Make sure not to overfeed and continue testing water parameters.

Notes and sources

  • Fish tank size recommendations from Aqueon and Marineland tank manufacturer sites
  • Water parameter ideal ranges and testing frequency tips via the API Freshwater Master Test Kit Manual

General aquarium maintenance routines from experienced fishkeepers on Reddit and other forums

Additional info verified against multiple aquarium books and online guides to ensure accuracy