Getting started with your first aquarium can be an exciting yet daunting task.
From choosing the right tank size to cycling the aquarium, there are some key considerations for aquarium beginners to get right in order to create a healthy habitat for the fish.
This comprehensive guide will walk you through the entire process and answer common questions new hobbyists have when setting up their freshwater tank for the first time.
Choosing the Right Tank Size

One of the first decisions you’ll make is what size tank is best to start with.
Small desktop tanks under 5 gallons are not ideal for beginners since water parameters can fluctuate rapidly.
For your first tank, aim for a larger 10-29 gallon aquarium, which gives you more stability and room for a few fish.
The extra water volume also dilutes fish waste and other contaminants, which makes maintaining water quality easier. Some good starter sizes include:
- 10-gallon tanks – Gives you flexibility for small community fish or betta tanks.
- 20-gallon long – Provides lots of horizontal swimming space.
- 29-gallon standard – Allows slightly larger or more fish.
I personally started out with a 20-gallon tank, which gave me enough room for a small community of tetras and live plants.
Make sure you also have a suitable cabinet or stand that can safely hold the total weight.
Once you’ve chosen a tank size, determining the equipment you need is the next step.
Basic Equipment Needed for Freshwater Aquarium
Lighting

Having proper aquarium lighting serves both a functional and aesthetic purpose.
Fish need light for their circadian rhythms, while lights also let you view your tank.
Low to moderate light levels are recommended for starter tanks with beginner species.
Some lighting options include:
- Incandescent hoods – Inexpensive with replaceable bulbs.
- LED fixtures – Efficient and long-lasting with bright illumination. Intensity can be customized.
- Natural light – Can supplement weaker tank lights but may promote more algae growth.
I use simple LED lights on most of my tanks, which provide great brightness and visibility without the need for bulb changes.
Heaters

Heaters are necessary to maintain a stable, optimal temperature range for tropical freshwater fish species.
I recommend choosing a heater with a higher wattage than your tank size requires.
This prevents the heater from constantly working to maintain the set temperature.
For example, a 29-gallon tank may only need a 150W heater, but running a 200W unit provides a buffer.
Use submersible heaters and set them between 72°F to 82°F, depending on your fish species. Check manufacturer guidelines for sizing recommendations.
Filters

Filters are arguably the most vital component of aquarium equipment systems.
Their primary purpose is to process fish waste and debris through mechanical, biological, and chemical filtration.
This keeps water conditions clean and non-toxic for inhabitants.
For starter freshwater tanks, hang-on-back power filters like the AquaClear provide excellent multifunctional filtration combined with ease of use.
Make sure to size your filter appropriately – higher gallons per hour (gph) ratings allow for bigger tanks and fish loads. And don’t skimp on filter media, either!
Getting the Right Decor
From gravel and substrate to decorations and plants, stocking your aquarium can be lots of fun.
Consider what visually appeals to you and represents a natural ecosystem while also keeping your fish species’ needs in mind.
Here are some decor tips:
Substrates

Gravel, sand, and other bottom substrates provide surface area for beneficial bacteria colonization apart from looking aesthetically pleasing.
Bare-bottomed tanks limit filtration capacity.
Popular aquarium substrates include:
- Natural gravel – Popular economical option for replicating riverbeds. Easy to clean.
- Colored gravel – Adds pop and visual interest. Can use different layers.
- Sand – Very natural look, especially with plants. Requires more rinsing/cleaning.
- Marbles – Smooth and uniform but unnatural. Best as accent substrates.
Whatever you choose, give new substrates a thorough rinse before adding them to your tank to prevent cloudiness issues.
Plants & Decor

Beyond substrates, incorporating things like live/artificial plants, rock formations, driftwood, and aquatic ornaments can really make your aquarium stand out.
This is where you can get creative in crafting natural biotopes or themed setups.
Live plants help with water quality, provide fish shelter, and replicate natural environments.
I recommend hardy, low-light beginner species like Java Fern, Anubias, Amazon Swords, Cryptocorynes, and more.
Make sure any man-made decorations have soft edges and don’t compromise water quality.
Allow for open swimming areas along with planted zones. Crafting the ideal aquascape takes some practice but adds immensely to aesthetics.
Take your time playing around with decor arrangements till you’re fully satisfied. The end results are well worth it!
Filling Up the Tank
Once your tank is fully decorated, you’ll want to fill it up with water. Use room temperature dechlorinated water only.
To dechlorinate, use water conditioners that neutralize chlorine/chloramines and also contain beneficial slime coats for fish.
Products like Seachem Prime or API StressCoat are ideal.
Follow the dosing instructions on the bottle based on total tank size – don’t just dose for the water volume you’re adding!
This step helps make tap water safe for inhabitants when filling up the tank.
Cycling Your Aquarium
Before you can add fish, a nitrogen cycle needs to be established first.
The cycle facilitates the growth of essential nitrifying bacteria that convert ammonia and nitrites – byproducts of fish waste and respiration – into safer nitrates.
Cycling helps create a balanced ecosystem that breaks down and processes biological waste.
Learn more about the specifics of fishless or fish-in-nitrogen cycling, but expect the process to take anywhere between 2-6 weeks after filling your tank.
Keep checking parameters until ammonia and nitrites consistently read 0ppm and some level of nitrates is present.
Choosing Suitable Fish

When first starting out, select hardy fish that can tolerate some of the beginner mistakes made during the tank establishment phase.
Avoid aggressive species or ones requiring advanced care for now.
Some great starter freshwater fish include:
- Zebra Danios
- Platies
- Swordtails
- Guppies
- Corydoras Catfish
- Small Tetras
For community tanks, stick to just a few small schools first instead of overloading your new tank with too many fish.
Give your tank some time to season and build up its biofilter capacity through regular feedings and maintenance.
Once settled in, feel free to experiment with more fish species you like!
Feeding & Maintenance

To keep your tank ecosystem thriving:
- Feed fish-appropriate foods in moderation, once or twice daily only. Provide only as much as they can finish within a few minutes.
- Perform 10-25% partial water changes weekly, depending on stocking levels, using a gravel vacuum to siphon waste from the substrate.
- Prune or thin plants when overgrown. Wipe down the glass when algae build up.
- Check water parameters weekly at first for anything abnormal. Monitor ammonia, nitrites, nitrates, and pH.
- Supplement tanks with beneficial bacteria, algae control, or mineralizing products as needed for upkeep.
Above all, enjoy interacting with your new fish and watching them grow!
Part of the fun with the hobby is continually building upon what you started as you gain experience.
Before you know it, you may even try advanced setups like cichlid tanks, planted aquariums, and reef systems.
But everyone has to begin somewhere – hopefully, this guide gives you a solid foundation for freshwater fishkeeping success!