How to Set Up a Freshwater Fish Tank

Setting up a freshwater fish tank can be an exciting yet daunting task, especially for beginners. This comprehensive guide will walk you through the entire process, from choosing the right tank size to adding live plants and fish. Whether you’re a first-timer or looking to upgrade your current setup, this guide covers you.

How to Set Up a Freshwater Fish Tank

Choosing the Right Tank

Choosing the ideal fish tank for your needs and space is the first step to setting up a freshwater aquarium. Here are some factors to consider when selecting a tank:

Tank Sizes

Popular tank sizes for beginners include:

  • 10 gallon – Best for housing 1-2 small fish like bettas or guppies. Easy to maintain.
  • 20 gallon – Allows for more fish. Suitable for small community fish or single-species tanks.
  • 29 gallon – Ideal beginner tank for community fish. Provides more room than 20 gallon.
  • 40 gallon breeder – Wider footprint is great for aquascaping. Fits medium sized fish.
  • 55 gallon – Large tank for community fish. Allows aquascaping flexibility.
  • 75 gallon – Enables schools of small fish or medium semi-aggressive fish.

Consider the full adult sizes of your desired fish when choosing a tank. Generally allow 1 gallon per inch of fish.

Glass vs. Acrylic

Glass aquariums are classic but heavy. Acrylic tanks are lighter but scratch easier.


  • More affordable option
  • Range of sizes available
  • Sturdy and long-lasting
  • Can be very heavy when full


  • Lighter than glass
  • Impact resistant
  • Seamless corners
  • Prone to scratches

For first timers, a standard glass tank is usually the best choice. Make sure the tank is level and supported properly.

Essential Equipment

In addition to the tank itself, you’ll need some vital pieces of equipment to create a healthy aquarium environment:


A strong filtration system is crucial for removing waste and keeping water clean. A hang-on-back (HOB) power filter is usually sufficient for freshwater tanks. Make sure the filter is appropriately sized for your tank.

Other options like canister filters and sponge filters also work well. Having extra filtration capacity is always better.


Heaters help maintain a stable water temperature between 76-82°F, ideal for most freshwater fish.

Use a submersible aquarium heater that can be adjusted and is sized for your tank volume. Place it near water flow for even heating.


Proper aquarium lighting serves aesthetic purposes and provides light for live plants and fish health.

For basic illumination, an LED hood or clip-on light works well. Go for full spectrum or plant growth LEDs if keeping live plants.

Air Pumps

Air pumps are not mandatory but provide extra aeration, circulation and gas exchange, benefiting fish health.

An air pump with an air stone or bubble wall generates bubbles and surface agitation. This also improves tank oxygenation.

Water Source and Treatment

The source and condition of the water entering your tank is extremely important. Here’s an overview:

Tap Water vs. Distilled Water

Tap water is the most convenient option but may contain chlorine, heavy metals or other contaminants unsafe for fish.

Distilled water is purer but lacks essential minerals needed for aquatic life.

Many experts recommend using tap water treated with products like water conditioner which removes chlorine and neutralizes heavy metals. This provides clean, safe water with balanced minerals.

Water Conditioners

Before adding tap water to your tank, use water conditioner to remove chlorine and chloramines. Popular brands include Seachem Prime and API Stress Coat+.

Water conditioner also binds heavy metals and adds essential electrolytes. Read the product label for correct dosage instructions.

Dechlorinated tap water is perfectly fine for most freshwater aquariums. Just be sure to treat all new water added!

Substrate and Decor

Choosing appropriate tank substrate and decorations provides aesthetic appeal while positively impacting fish health.

Gravel vs Sand

Gravel is the classic aquarium substrate. It allows effective waste filtration and is available in various attractive colors and sizes. Popular options include natural round pebbles or coated gravel.

Sand is also common. It gives a smooth minimalist look. Play sand or pool filter sand are economical choices. Sand may need regular stirring to prevent compacting.

Whichever you choose, rinse the substrate well before adding it to your tank.

Adding Rocks and Driftwood

Natural additions like rocks, stone and driftwood make excellent decorations. They also provide hiding spots for shy fish.

Use smooth river rocks or slate pieces. Be sure rocks are aquarium-safe and won’t affect water chemistry.

Driftwood adds tannins beneficial for some species like tetras and bettas. Boil and soak new driftwood before placing in your tank to avoid issues.

Live Plants vs Artificial Plants

Live aquarium plants have many benefits compared to artificial decor:

Benefits of Live Plants

  • Improve water quality by absorbing nitrate and ammonia
  • Add oxygen to water
  • Provide fish with hiding spots and security
  • Help complete the nitrogen cycle
  • Enhance overall aesthetics

Easy low light beginner plants include:

  • Java Fern
  • Anubias
  • Amazon Sword
  • Cryptocorynes
  • Java Moss
  • Hornwort

Avoid fully aquatic plants like red ludwigia and dwarf baby tears for starter tanks.

Chemicals Needed

Using the right chemical supplements is key to maintaining proper water parameters. Here are the basics:

pH Adjusters

Test water pH regularly. Ideal is 6.5-7.5. If pH is too low, gradually raise it with pH Up. If too high, lower with pH Down. Make adjustments slowly over time.

Ammonia Removers

New tanks experience ammonia spikes from the nitrogen cycle. Use ammonia locking chemicals like Seachem Prime to detoxify ammonia into a safer form.

Algae Control

Limit light duration to 6-8 hours daily. Remove excess nutrients causing algae overgrowth. Algaecides can be used sparingly to kill nuisance algae if needed.

Research any chemical additives fully before using to avoid inadvertently harming fish.

Setting Up the Tank Step-by-Step

Once you have all the components, it’s time to set up your tank. Take it slow and steady:

Initial Setup

  1. Rinse out the empty tank thoroughly with water, no soap.
  2. Add the rinsed substrate and decorations like rocks, driftwood and plants.
  3. Fill tank slowly with treated tap water. Leave space at top for equipment.
  4. Install filter and heater fully submerged. Position near water flow.
  5. Consider adding air stone connected to pump. This adds oxygenation.
  6. Let tank sit 24 hours and recheck water parameters before adding fish.

Adding Water

  • Fill tank no more than 90% full, leaving space at the top.
  • Use room temperature dechlorinated tap water.
  • Pour water gently over a dish or decor item to avoid disturbing substrate.
  • Check for leaks, top up water to compensate for evaporation before adding fish.

Installing Equipment

  • Install filter and heater completely submerged with water flow unobstructed.
  • Position heater near filter outlet to distribute heat evenly.
  • Make sure lighting is secured above tank or clipped on securely.
  • Check that air pump is hooked up and pushing air through the air stone.
  • Ensure all equipment is plugged into a surge protector, not an extension cord.

Step-by-Step Summary

  1. Set up and level empty tank
  2. Rinse and add substrate, decor
  3. Fill partially with dechlorinated water
  4. Install filter, heater, lighting and air stone
  5. Let cycle 24 hours and recheck water
  6. Only add fish after parameters are ideal

Take it slow and follow this process to avoid costly mistakes!

Waiting Time for New Fish

It’s important to wait until your tank is fully cycled before adding fish. Here’s what you need to know:

The Nitrogen Cycle

In the nitrogen cycle, beneficial bacteria convert toxic ammonia from fish waste into safer nitrites and nitrates. This establishes the biofiltration needed to support fish.

Cycling a new tank takes 4-8 weeks for bacteria colonies to populate fully. Skipping this period will cause ammonia spikes that can kill fish.

Testing Water Parameters

Only add fish after fully cycling your tank and testing to confirm:

  • 0 ppm ammonia
  • 0 ppm nitrites
  • <40 ppm nitrates
  • pH between 6.5-7.5

Use liquid test kits not strips to check levels. Significant ammonia indicates the tank needs more time to cycle before adding fish!

Types of Fish

Choosing suitable freshwater fish for your tank is key for health and compatibility. Here are some top beginner choices:

Community Fish

  • Guppies
  • Mollies
  • Platies
  • Swordtails
  • Tetras
  • Rasboras
  • Corydoras catfish
  • Bristlenose plecos

These are peaceful shoaling fish perfect for community tanks. Mix species with similar size, temperature and water needs.

Schooling Fish

  • Neon tetras
  • Rummynose tetras
  • Harlequin rasboras
  • Cardinal tetras
  • Glowlight tetras

Schooling fish thrive in groups of 6 or more of their species. Their synchronized swimming is mesmerizing.

Aggressive Fish

Avoid the following until you have experience:

  • Oscars
  • Jack Dempseys
  • Convict cichlids
  • Green terror cichlids

Aggressive cichlids need larger individual tanks with only semi-aggressive tankmates.


Though often sold as beginner fish, bettas have specific care needs.

Consider a species only tank for a male betta. Female bettas can be kept in small peaceful community tanks.

Aquarium Kits: Worth It?

All-in-one aquarium kits promise to simplify setup but are they truly beginner-friendly?

Pros of Aquarium Kits

  • Convenient all-in-one purchase
  • Contains essential components
  • Often affordably priced

Cons of Aquarium Kits

  • Equipment quality can be low
  • Limited filter capacity
  • Basic incandescent lighting
  • Heaters may be substandard

Avoid cheap kits and purchase key items like filter and heater separately based on tank size for best results. Quality matters over convenience for fish health.

Recommended Kits

The Fluval Flex and Aqueon Frameless Cube kits offer nicer LED lighting and appropriate filters for starter tanks. Go for the larger 9-15 gallon kits.

Video Guides for Help

If you learn better from visuals, watching fish tank setup tutorials can be extremely helpful:

Top 5 YouTube Channels

Aquarium Co-Op – Practical guides for beginners

  • Avoid starting with CO2 injection, focus on good lighting and some fertilizer.
  • Choose a cube or deep aquarium for better aquascaping depth.
  • Build depth by placing taller plants at the back and shorter ones in front.
  • Be patient with your aquascape; it takes time to refine and maintain.

Prime Time Aquatics – Upbeat and engaging videos

  • Tank size matters, and nano tanks are great for home offices due to their compact size.
  • Consider the placement of your tank carefully; ensure it’s not distracting and away from direct sunlight.
  • Choose fish appropriate for your tank’s size and won’t be too distracting in a home office environment.
  • Check if your desk or cabinet can withstand potential water damage from tank maintenance.
  • Plan for managing multiple cords associated with the tank, keeping aesthetics in mind.

Green Aqua – High-end aquascaping tutorials

  • This video serves as a guide to navigating the channel’s content, aimed at both newcomers and experienced aquascapers.
  • The speaker shares their journey in aquascaping, emphasizing the importance of gaining experience over time.
  • Newcomers can start with a curated playlist of essential videos covering various aspects of planted tanks.
  • The playlist offers a starting point but mentions that more advanced topics are covered in other videos, like RO systems and contest tank setup.

SerpaDesign – Creative aquarium inspiration

  • Building DIY aquariums can save money, but working with glass or acrylic can be intimidating for beginners.
  • To create rimless aquariums without cutting glass, you’ll need silicone, a caulk gun, masking tape, a razor, paper towels, and isopropyl alcohol.
  • IKEA glass shelves can be used to build these aquariums without cutting. They are a cost-effective option.
  • Silicone application is crucial. Apply it along the glass edges and faces for assembly, and smooth it with your finger or an object.
  • Building these DIY rimless aquariums can be cost-effective, and the video provides cost breakdowns for different tank sizes.

Specialized Tanks

Once you have some experience under your belt, you may want to branch out into setting up tanks for specific fish:

Goldfish Tanks

Fancy goldfish need:

  • Minimum 40 gallon tank
  • Powerful external canister filter
  • Fine gravel substrate
  • Cool water around 65°F

Provide sinking pellet food and many live plants to meet their high bio load.

Tropical Tanks

Many popular community fish like tetras, guppies, cory cats, and gouramis prefer warm tropical water around 78°F.

Use adjustable heater and low wattage LED or fluorescent lighting mimicking their natural habitat.

Aquarium Ideas and Themes

Personalizing your tank with unique themes and décor makes the hobby more enjoyable.

Color Schemes

  • Blue and green neon tank for glowfish
  • Blackwater biotope with driftwood for tetras
  • Natural sand and rock for cichlids
  • Bright coral décor for guppies and platies

Aquascaping Styles

  • Dutch style – Densely planted, organized look
  • Iwagumi – Rock formations as focus
  • Jungle style – Wild, overgrown look
  • Flexibility – Rescape anytime to change it up!

Time Required for Setup

Successfully setting up a new freshwater aquarium requires planning and patience:

Planning Phase

  • Researching fish species and tank requirements
  • Selecting proper equipment
  • Ordering supplies
  • Fishless cycling period

Execution Phase

  • Assembling clean tank
  • Installing equipment
  • Treating and adding water
  • Hardscape and planting
  • Acclimating fish once cycled

Expect the entire process to take up to 2 months from setup to adding fish for an enjoyable, thriving aquarium.


  • There are many important steps involved in properly setting up a freshwater aquarium. Take the time to do it right.
  • Choose an adequate sized tank and sturdy equipment specifically for freshwater use. Focus on proper filtration and heating.
  • Source and treat water carefully to remove chlorine/chloramines and heavy metals. This provides clean, safe water.
  • Allow the tank to fully cycle for 4-8 weeks before adding any fish. Only add fish once ammonia and nitrites show 0 ppm.
  • Stock the aquarium with compatible community fish or a betta for a beginner-friendly environment. Avoid aggressive fish.
  • Utilize online videos and guides to supplement this article. Gaining knowledge beforehand leads to aquarium success!

With research and patience, soon you’ll have a thriving freshwater tank. Just take it one step at a time. Enjoy this relaxing rewarding hobby!