Setting up your first goldfish tank is pretty straightforward, the biggest mistake I see over and over again is people buying a tank that is far too small.
Goldfish Tank Setup Guide
Here’s what you need to set up a goldfish tank;
- Tank
- Filter
- Dechlorinator / Water Conditioner
- Heater (depending on goldfish type)
- Substrate (optional)
- Plants (optional)
- Decor (optional)
- Lighting (optional)
- Lid (optional)
1. Choosing a Goldfish Tank
First and foremost, you must pick a suitably sized tank for your goldfish.
You are best to buy a tank that will be suitable for your goldfish once it is fully grown.
Goldfish can grow quite large, so if you buy a smaller tank now, you’ll only end up paying out for a bigger tank down the line as they outgrow it.
Not only is it more costly, but it’s a hassle to go through the tank setup process again.
Here’s a rough tank size chart for beginners, depending on what type of goldfish you have.
| TYPE OF GOLDFISH | TANK SIZE |
| Small Fancy Goldfish | 20 gallons plus 10 gallons per additional fish |
| Large Fancy Goldfish | 29 gallons plus 10 gallons per additional fish |
| Single Tail Goldfish | 40-75+ gallons plus 12 gallons per additional fish |
When you first put your goldfish into a large tank, you will think it is way too big and looks empty, but trust me they will soon grow into it!
Glass Tank vs Acrylic Tank
Aquariums are available in both glass and acrylic, both having their pros and cons.
Glass tanks are lower in price, have way more size options to choose from, less likely to get damaged, but are much heavier.
Acrylic tanks are lighter making them easier to maneuver, but they scratch easier, are more expensive, and you don’t have as many options when it comes to tank sizes.
I don’t bother with acrylic tanks myself, but that’s just my personal preference.
2. Filtration
A filter keeps the tank clean and saves you from having to change the water every couple of days to remove harmful toxins that build up.
When fish poop and leftover food begins to rot, this releases ammonia which is toxic to fish, a filter helps deal with this.
Goldfish need a decent quality filter, they are known to poop quite a lot (due to them being very greedy!).
The bigger your tank and the more fish you have, the more filtration you’ll need.
You have 3 choices of filter: canister, HoB, or sponge.
My preferred setup is a canister filter with 1-2 sponge filters.
Sponge filters are cheap, reliable, and great for beneficial bacteria and it means you always have a ‘seeded sponge filter‘ on hand, to quickly cycle a new fish tank or use in a hospital tank.
You can also add an airstone to a sponge filter, which is great for goldfish as they love oxygen-rich water.
3. Dechlorinator
A question people often ask is “Can goldfish live in tap water?”
Yes, they can. I only ever use tap water in my tanks.
To make tap water safe for fish, you must add a water conditioner (dechlorinator).
Tap water contains chlorine and other chemicals that keep it clean which is good for us, but harmful to fish.
Dechlorinating is simple. Fill your tank with water, and add the correct dose of water dechlorinator as per the instructions on the label.
My go-to water conditioner is SeaChem Prime. I’ve used it for years.
Seachem Prime is an essential item for ALL fishkeepers!
It removes chlorine and chloramine from tap water.
It detoxifies ammonia, nitrite & nitrate, making the aquarium water safe for your fish.
Directions: Add 5 ml per 50 gallons (200 liters) for regular detoxification.
Up to 5 times the dose (25 ml per 50 gallons) can be used in an emergency if ammonia or nitrites exceed 2 ppm.
- Easy to use
- Removes chlorine & chloramine
- Detoxifies ammonia, nitrite & nitrate
- Doesn't expire (if stored correctly)
- Suitable for fresh & saltwater aquariums
- Strong sulphur smell
4. Heater
Not all goldfish require a heater, it depends on the type of goldfish you keep and the temperature of your home.
For single-tail varieties like common, comet, and shubunkin goldfish the optimum water temperature range is 64°F to 70°F (17.5°C to 21°C), which can usually be maintained without a heater.
For fancy goldfish, the optimal range is 68°F to 74°F (20°C to 23°C), so a heater can be useful to help maintain the ideal temperature.
5. Substrate
Substrate is optional, you can leave the tank bottom bare if you like.
When it comes to choosing substrate I always go with fine sand over gravel or rocks for the following reasons:
- It replicates the fish’s natural environment.
- Goldfish love to spend their day picking over the substrate and searching for any scraps of food. Small pieces of gravel can become stuck in their mouths causing them to choke.
- Sand compacts a lot more so there are no gaps for uneaten food and fish poop to get trapped in making it easier to keep clean.
- Gravel and rocks can have sharp edges that can tear your goldies’ delicate fins.
Darker sands will make your fish’s colors pop, but that’s down to personal preference and the look you’re after.
A great option for fine aquarium sand is Carib Sea Super Naturals.
It’s super soft, pH neutral and 100% free of artificial dyes, paints, or coatings so it won’t leak nasty chemicals into your water so it’s perfectly safe for your fish.
You do need to rinse it several times before adding it to your tank, to avoid it making the water cloudy.
6. Plants
Fake or live plants, the choice is yours!
Live plants bring many benefits to an aquarium whereas fake plants are just for decoration.
If you choose to buy fake plants, then Marina Naturals is my No.1 choice.
They’re natural-looking and are made of safe, non-toxic silk material that will not injure your goldie.
For live plants, you have many options including:
I would advise you to attach live plants onto rocks, driftwood, or decor, as your goldfish will uproot the plant as they sift through the substrate looking for food.
Live aquarium plants have many benefits, including:
- Removing harmful nitrate
- Removing carbon dioxide
- Adding oxygen
Some plants also provide an additional food source, goldfish love to eat duckweed.
7. Decor
When it comes a decorating a goldfish tank, you can choose any style you like, but there are a few things to take into consideration.
Remember not to take up too much swimming space (leave 75% for swimming), and avoid sharp and rough edges that could injure your fish.
Choose decor items that your fish won’t get stuck in (no small holes they can squeeze into), fancy goldfish are not the most agile swimmers and the last thing you want is for them to become trapped inside a decoration!
8. Lighting
An aquarium light isn’t needed for a goldfish tank unless you have live plants.
Fish tank lights are mainly for our benefit so we can see our fish.
If you do decide to have lights on your goldfish tank get a programmable LED fixture as they are far more economical to run than non-LED light fixings.
My go-to choice of light fixture is the Hygger LED aquarium light.
It has:
- Various size options for different tank sizes
- Full spectrum of light coverage
- 5 options for how bright you want your lights
- 3 timer settings of 6 hrs, 10 hrs, or 12 hrs
I like the default 24/7 mode too. Just switch it on and it will automatically adjust the light color to what time of day it is, which is a great benefit to your fish’s circadian rhythm (their natural day/night cycle).
- Gradient orange light (sunrise) from 6 am to 8 am
- Gradient white light from 8 am to 6 pm
- Gradient blue light (moonlight) from 6 pm to 10:50 pm
- Lights out from 10:50 pm to 6 am
9. Aquarium Lid
Aquarium lids are not essential for goldfish tanks, as goldies aren’t known for being escape artists.
The main advantages of a cover are it stops your fish from escaping, keeps your fish safe from other pets, and helps reduce natural water evaporation.
The drawback is that it hinders the gas exchange process so your water won’t be as oxygenated.
What To Do Once Goldfish Tank Is Set Up
There are a few things to do and monitor once your tank is set up.
Cycle Your Tank – Very Important!
Now you’ve set up your goldfish tank, it’s not ready for your goldfish just yet.
You need to cycle your tank first (method no.1 is the quickest and easiest way) and establish the nitrogen cycle that will deal with the ammonia that fish waste and decaying food will produce.
You must cycle your tank before adding your goldfish, if you don’t you’ll quickly run into what’s known as new tank syndrome, which is when you haven’t colonized enough beneficial bacteria to deal with the amount of waste being produced, causing harmful toxins to build up in the tank, which is deadly for your fish.
Monitor Water Parameters
Once the tank is cycled it’s your job to maintain the ideal goldfish water parameters, to ensure your pet goldfish stay healthy.
| WATER PARAMETER | TARGET |
| Temperature | Optimal Range 64°-74°F (17.5°-23°C) |
| pH Level | 7.0-8.0 (7.2-7.6 ideally) |
| Ammonia | 0ppm |
| Nitrite | 0ppm |
| Nitrate | Below 40ppm |
Maintain Safe Water Parameters
To maintain safe water parameters, you need to clean your goldfish aquarium and perform water changes.
How often this will be depends on a few factors, such as tank size, stocking levels, and the quality of your filter.
Ammonia and nitrite buildup will kill your fish, nitrate is less harmful until levels build up too high.
The only way to get rid of nitrates is through water changes and by adding live plants, such as pothos.
Where To Locate Your Tank
You should place your tank in a quiet area where it will get plenty of natural (but not direct) sunlight, on a level, and sturdy surface that can support the weight of the tank and the water.
- 1 gallon of water weighs 8.34 lbs (3.8kg)
- 20 gallons weight 167lbs (76kg)
- 40 gallons weighs 334lbs (152kg)
I advise against placing the tank in direct sunlight, near windows, doors, heaters, air conditioners, or vents as they can cause temperature fluctuations that can stress the goldfish.
Closing Thoughts on Goldfish Aquarium Setup
Now you know how to set up a tank for goldfish correctly, you need to keep on top of cleaning and maintaining it, so your goldie will thrive and be happy.
The key points to remember are:
- Goldfish grow large so a small tank or bowl isn’t the right home for them.
- A larger tank gives them more space to swim and thrive in and is also much easier to maintain stable water parameters.
- Test the water every day, to begin with, record your parameters, and build a maintenance schedule. If you add more fish, your schedule will change due to the increased bio-load.
- You should aim for ammonia 0 ppm, nitrite 0 ppm, and nitrate below 40 ppm. Perform water changes every time the nitrates reach 40 ppm.
- Keep the pH and temperature consistent, don’t be constantly chasing ‘the perfect number’. Small fluctuations cause big stress to fish.
- Keep water conditioner in stock at all times. You’ll need it after every water change when refilling the tank.
- Cycle your tank before you add a goldfish to it and avoid running into new tank syndrome.
Check out the Aquarium Health section for more guides just like this one, to keep your tank in tip-top shape.
