How to set up your first Aquarium
Updated: Apr 24
There's so many benefits to keeping pets for people of all ages. For adults the calming lives of fish and their often beautiful homes prove to have calming effects, reducing stress. Studies also show that they benefit the condition for Alzheimer's patients too. There's even benefits for children - their first fish tank will encourage learning and help them deal with negative emotions. They also learn the responsibility of looking after their own little pet.
There's a huge range of aquariums out there and equal if not more types of fish to put in them which ensure that whatever colours and shapes you're after, you can probably get it in the world of aquariums.
In this article, we're going to walk you through preparing whichever tank you've chosen, installing your equipment, a step that most new fish owners miss - cycling the tank, and finally acclimating your new fish. Unfortunately many fish stores will sell fish to customers as they're buying the tank, or to owners who've only just picked out their tank a few days beforehand.
We'll explain why this isn't ideal and how it's important to carry out a full cycle before you add the fish to your tank. This is a step that a lot of new fish owners miss out but it can be one of the most important steps in getting your tank up and running into a thriving environment.
Step one: Which fish?
The first step on your new pet journey should not be which tank you want to pick out, but which fish you plan to keep in there. What types of fish are you planning on keeping in there? Will it be a community of fish? Just a couple of small species of fish? Will you be breeding them? The type of fish and invertebrates you decide you want to keep will then govern how big of a tank you'll need and what sort of equipment you'll need. To work out how many of a specific fish you can buy, we always go for the "2 gallon per inch" rule. Find your chosen species' maximum length and make sure you have at least 2 gallons of space for them in the tank.
For a list of the Best Fish for Starter Aquariums, click here.
If the tank you want to buy is small, you can use a similarly sized piece of paper to plot out where decorations can go, which will help you size them up when buying. Depending on the type of fish you buy, you might need a heater. You'll probably need a filter and either some ornamental decorations or some plants will give your fish more to explore. Some people opt for air pumps for their tanks, but depending on the filter you buy and where you position it, you may not need one as you can sometimes oxygenate the tank enough by having the filtered water splash back down into the tank water. Plants will also help keep the water oxygenated but this can be a difficult thing to balance if you're relying on them solely.
Step 2: Rinse Clean
Once you've bought all of your equipment it's time to start putting it all together. Before you start adding things to your new tank, they'll need to be fully cleaned. Tanks can be wiped down with a wet cloth, never use any chemicals inside the tank - just water. Outside of the tank you can dilute white vinegar and use a cloth to keep it sparkling. For the ornaments, let them soak in hot water and give them a rinse afterwards, even if they're new. You want to be sure that nobody has left any cleaning sprays on them while they've been cleaning the shop.
If your tank is second hand then you'll need to be a bit more thorough and pay attention to details. If your tank is acrylic instead of glass then you'll need to use softer cloths to make sure you don't scratch the tank. Remove any debris from the tank and rinse around the sides with diluted vinegar, giving it a rub with your cloth as you go. Once you've cleaned the tank you need to check that it's leak proof, even if it's new. Tanks can sometimes come with manufacturing issues and it's a lot less stressful finding them before you've put anything in!
Simply fill the tank up with a few inches of water and leave it to sit for an hour. Run your fingers around the bottom edge after to see if any water's leaked out. If you do find a leak, it's not the end of the world - just use some aquarium sealant (Found here for US, and Here for UK) to reseal the tank around its edges.
Step 3: Position the tank in place
Now it's time to position your tank where you want it to stay for at least the next few weeks, but preferably at least several months. We're going to move it now because although tanks can seem small, even 20 liters of water can be heavy and quite difficult to move. Make sure you're placing the tank out of direct sunlight, and somewhere near a power supply.
You'll also need to make sure where you're putting the tank is strong enough to take the weight because putting water in adds a whole lot of weight - a 50 gallon tank can weigh around 100lbs when empty, but around 600lbs when full! If you're using a beginners tank or a child's tank then you're probably okay to have it on something like a kitchen counter or a table. If it's a large tank you might want to get a purpose built stand for it.
Step 4: Check that it's level
Once it's in place, check that it's level. You can either do this with a spirit level, or just fill it with a few inches of water and judge it by eye. You want it to be level from left to right but also front to back - a lot of people miss this out and it can throw off your filters if you have them at the back when the water’s too low there.
Step 5: Add your Substrate
Once it's clean, in the right position and it's level, you can add the substrate to the tank. Right now is an important time to mention that if your filter is an under gravel filter, you need to add this now. For all other filters, this will come after. You can check out Under Gravel Filters here, they have some pretty nice benefits. The substrate is the soil or gravel that you've bought. Be sure to rinse that through first too.
Just pour it into a bucket, add water till its a few inches above the substrate then mix it round by hand. If it's visibly dirty then empty some water out and add more fresh water in, until the water in the bucket looks clear. Bear in mind that some powder coated gravels don't do well with being washed vigorously, just be sure to rinse them as best you can.
If you can lower the whole amount of substrate into the bottom of the tank to empty it, that's fine. If you can't get the whole package into the tank, then pour it into a bowl, lower the bowl into the tank then empty it. By emptying it out from above the tank you can cause damage.
The substrate you choose should depend on what type of plants and fish you've bought - though things like colours of gravel are purely personal choice. For example if you're using live plants, they'll need a soil type of substrate or at least a section of it. If you're using fish that eat from the bottom of the tank then you'll need bigger gravel so they don't accidentally get a mouth full of it. Try to have at least an inch of substrate at the bottom of the tank. Some people like to build the substrate up towards the back to create a better sense of depth in the tank. Be as creative as you want, but keep the lowest part at least an inch thick.
Step 6: Add Water
Now it's time to add water.For freshwater, Place a bowl on top of the substrate so that you don't pour directly onto the gravel as this can disturb it and also scratch the bottom of the tank. pour into the bowl until you have a few inches of water in there, then you should get by with slowly adding the water. After this you'll want to do your water checks for pH levels and dechlorinate the water. For saltwater it's a little more complicated. You'll need to use either reverse osmosis or deionised water, only use tap water if you're sure the water quality is excellent. You'll then want to add your sea salt mix to the water before adding it to the tank. A lot of people have several buckets that they prepare the water in before adding it to the tank. When your saltwater's ready, just add it to the tank in the same method as above.
Shopping guide for water treatment:
Water treatment - We use Either Tetra AquaSafe for this or Seachem Prime (see below)
pH Level Testing kits - We Use API Master Test Kits.
Step 7: Add your equipment
When the water's in you can start adding equipment. These are things like your heaters and filters - leave the decorations and plants til last. Set up your filter in a way that will either blow water out above the tanks level, to create the bubbling effect that boosts oxygen levels, or keep it in a place where the current won't frustrate your fish. If you've got a bubble bar you can use this to break up the current from the filter. If you've got a heater you'll want to either place this in the specified area for that tanks design (some tanks for example have back sections where the filters and heaters go) or just place it at one side of the tank. Be sure to place a thermometer at the other side of the tank. This helps to make sure that the tank heats up evenly and doesn't have a cold spot.
Always make sure that the filter is correctly installed before you switch everything on, as quite often the motors are cooled and lubricated by the water - taking in a lot of air will break these motors. Some filters are external and these are often easier to clean and perform better as being compact isn't a huge design aspect. Most external filters need to be full of water before you switch them on. If you're opting for internal filters, make sure you can circulate the entire content of your tank 4 times in one hour.
If you've purchased anything else equipment wise, such as an air pump or lights, do this now. If you have a protein skimmer for your saltwater tank then include this too.
Shopping list for Equipment:
For air pumps you don't need anything special for the most part. This option would do just fine.
Step 8: Add your decorations
You’ve set up all the operational, functional parts of your tank, now it’s time to make it look good. You might opt for focussing on a planted tank and getting some big rocks and driftwood in there for a natural look, or you might go for a basic castle and fake plant style decor. Whatever your choice, it’s time to put it in place.
Be sure to rinse each item before you put it in the tank. If you’re placing decorations such as rocks, sculptures or driftwood, you’ll want to push that a few centimeters under the surface of the substrate/gravel. This will help cement them in place so no currents from the filter or pumps can move them around. For plants, you’ll want them to dig in further to stay planted. Ideally you will have created thicker areas for where you want the plants, so you can just push their pots (if they have them) below the surface and cover the base over.
Carry out research on the plants you’ve bought and look into the specifics of where that species should be placed. Moss for example, like java fern, usually needs to cling to something, so you’d super glue parts of that to things like driftwood.
Step 9: ALWAYS Cycle
Now that everything’s in place it’s time to cycle the tank. Most pet stores recommend running the tank for 24 hours before adding the fish - this isn’t advisable. To correctly cycle the tank it takes a fair bit longer, but it means your fish come into a home that’s suitable for them to be able to thrive. It’s fairly straight forward but some science is involved. Don’t worry, we’ll walk you through it.
Cycling the tank means you are building up a bacteria ‘bed’ in your biological filter which is essential for the health of your future fish. Firstly your filter will grow a culture of bacteria which converts ammonia into nitrites. Then it will culture bacteria which converts nitrites to nitrates. Both ammonia and nitrites are toxic to fish so it’s important you run a full cycle to allow these bacteria to develop.
Nitrates are still toxic to fish, but only in high levels, which is why it’s important to carry out regular water changes to remove them. We always recommend cycling your tank without fish, so they are not exposed to any of the toxins.
To begin the process, add some ammonia into your tank, this is readily available in almost all fish stores and only cost $2-$3(£1-£3). Follow the instructions on the bottle as some recommend that you add a large dose at the start, others recommend adding a certain dose per day. Perform tests on a weekly basis to check the levels, you’ll see the ammonia and nitrite levels spike and then start to drop. Once they reach zero (0ppm), your tank is fully cycled.
To speed this up you can either donate filter media from an established tank you have or use an air stone or pump to increase the oxygen levels. Increasing the water temperature will also help. This whole process takes around 6-8 weeks. Once you’ve checked your ammonia and nitrite levels are at 0ppm, perform a 50% water change to remove any build of nitrates.
We always opt for API's Master Test Kits for monitoring Ammonia, Nitrite and Nitrate levels. They also show you pH levels and water hardness too!
Step 10: Add your Fish!
Now it’s time to add your fish! This is the step you’ve been so patiently waiting for! You’ve probably invested quite a lot of time and money into your setup and are excited to introduce fish to your tank.
You need to make sure you add your fish slowly over a period of a few weeks (or months); the amount you can add depends on the size of your tank. Start off by adding no more than one inch of fish per 10 gallons.
You then need to acclimate your fish. The purpose of acclimation is that fish are sensitive to any changes in their water, so moving them from one tank to another should be done slowly. It’s likely that the water they are currently in is slightly different to your tank temperature, pH and salinity parameters.
If you want to be on the safe side, you can quarantine fish in a separate aquarium for a couple of weeks to observe them. Some people like to do this to ensure they are not showing signs of disease.
There’s usually instructions on the bag that you get your fish in, however here’s how you can acclimate your fish:
• Turn off the lights and keep the room dim.
• Float the bag in the tank for 15 minutes to let it change temperature to match the tank.
• Open the bag and add a cup of water from your tank to the bag.
• Wait 5 minutes then do it again.
• Repeat this until the bag is almost full, then pour out half of the bags water (not into the tank, typically just down the sink).
• Repeat the steps of adding a cup at a time until the bag is full again.
• Using a net, take out one fish from the bag and put them in your tank.
• Discard the bag full of water and top up the tank if needed.
• Discarding the water both times ensures nothing tiny that might be hiding in there makes its way to your tank (we’re looking at you, snails).
All set! Keep an eye on your fish for the next 24 hours to make sure that they’re settling in well and eating properly.
You’re all set! Well done!
This can seem like a lot of time just to set up a fish tank, but particularly the cycling step is important in making sure your fish stay happy and healthy. If you were to take 5 points from this entire article, these should be:
Plan out exactly what you want from your tank before you buy anything.
Always place the tank in its permanent position before filling it.
Make sure your equipment is properly installed before switching anything on.
ALWAYS ensure your tank is fully cycled before adding any inhabitants.
Acclimate your fish slowly so they don’t become stressed.
Thanks for checking out our guide. If you're new to fishkeeping then here's a handy list of the Top 10 Aquarium Fish for Beginners. If you'd like to know which species you can buy that would help keep the tank clean, you can read about Aquarium Tank Clean up Crews.
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