How to Install Your Aquarium (Without Screwing It Up)

Working on your first fish tank? Whether it’s big or small, freshwater or salt, the initial set-up can be a little nerve-wracking. But it’s worth it: fishkeeping is a wonderfully relaxing and educational hobby.

Let’s get that tank filled up! Below, you’ll find a step-by-step guide you can follow to set up your aquarium—without breaking it or flooding your house.

Did you know? The installation processes for freshwater and saltwater aquariums are very similar, so we’ll discuss both here. Whenever the proceedings vary for saltwater tanks, we’ll add a separate note. If you’re setting up a freshwater tank, you can go ahead and ignore those!

Choosing a spot

Whether you’ve already got all the gear on hand or not, it’s never too early to start thinking about where you want your aquarium to go. This is one of the more important tasks, because depending on tank size, changing your mind later can be very inconvenient. No one likes to drain a 100 gallons worth of water and move a hugely heavy aquarium around!

Here are a few important things to consider:

• Weight. For larger tanks, especially in apartment buildings, check whether your floor can actually handle the strain. Consider: a 50-gallon aquarium can weigh up to 600 lbs, and that weight is distributed in a pretty small area.

• Light & temperature. The area you have in mind should be free of drafts. It shouldn’t receive direct sunlight, because too much light is a huge algae growth catalyst and the water may even overheat.

• Fish comfort. Very high-traffic areas in the house aren’t ideal for most fish, which spook easily when someone walks past. They also don’t like nearby washing machines, slamming doors, and the like.

• Surface. If you’re not using a stand, which is fine for smaller aquariums, check whether the surface you’d like to place it on is level.

• Electricity. Are there outlets nearby, or can you easily run them to the desired spot? The average freshwater aquarium may need up to five plugs, saltwater even more.

• How’s the floor? As hard as you try to prevent it, some aquarium water is always going to spill. If the floor can’t handle water at all, you’ll have to think of a solution.

Set-up time!

If you’ve got all the gear ready (check out our shopping lists for freshwater and saltwater if not) and have found a sturdy place for your new fish tank, we can go ahead and get this show on the road. Let’s make you an aquarist!

The very first thing you’ll want to do is install the protective foam mat that often comes with aquariums, which will help prevent damage to the cabinet or whichever surface is below. You can cut one yourself if it wasn’t included.

Place the aquarium on the foam mat and install it as follows.

Tip: If you got a used aquarium, test whether it’s still watertight first (preferably outdoors). Tanks that have sat empty for a long time sometimes need resealing.

Preparation

1. If you’re using a stick-on background or want to paint the back of the aquarium black, do so now.
2. Rinse the substrate until the water runs clear. This will prevent dust clouds from being stirred up every time you touch the sand or gravel.

→ Saltwater tanks: Don’t rinse live sand and rock, as you’d wash away the beneficial bacteria. Normal, dry aragonite sand, however, will benefit from a quick rinse.

Aquascape

1. Spread a layer of substrate along the bottom of the tank. An inch or so at the front and slightly more at the back gives a sloped look that most aquarists prefer.
2. Arrange your hardscape (=driftwood*, rocks, and decorations). Aquascaping is a matter of practice and a good eye, so you may end up rearranging things multiple times. That’s fine!
3. If you’re using a 3d background, install it now.

→ Saltwater tanks: Live (or dead) rock will form your hardscape. Most aquarists like to create one large or multiple small islands to later place their corals on.

*Most driftwood floats for multiple days. If you don’t want it drifting around your tank, soak it until it sinks before introducing it.

Fill ‘er up

1. Fill the tank, which can take a good while if it’s quite large. We like to pour the water on a plate placed on the substrate so the hardscape doesn’t get knocked out of place.
2. Condition the water with a product that removes both chlorine and chloramine.

→ Saltwater tanks: use RO/DI water mixed with marine salt, as described in our article on mixing saltwater (or go for pre-mixed saltwater from the aquarium store). Evaporation is always replaced with fresh RO/DI, never salt water—otherwise the salinity would slowly creep upward.

Equipment installation

1. Extract the booklets that came with your filter, heater, and optional additional equipment. Assemble everything as described, except the active carbon filter pads that often come with filters—those shouldn’t be used all the time.
2. Install as described and leave the equipment running at all times (except when doing water changes). Be sure to use a GFCI power strip for safety, and install drip loops on all cables so water can’t reach the plugs.
3. Install the thermometer and mount the light if it didn’t come pre-mounted. The light is best placed on a timer, about 6-8 hours a day.

→ Saltwater tanks: turn on the protein skimmer, powerheads, and the like. Just keep the light intensity low or the lighting period short, or the strong lights required for growing corals may cause an algae explosion.

Finishing touches

1. Add any plants and other décor you haven’t installed yet. The plants’ roots should be covered, but don’t place them too deeply in the substrate or they’ll die off. Special, extra-long aquascaping tweezers come in very handy here!

→ Saltwater tanks: leave things as they are. Corals, like fish and other livestock, can be introduced only when the tank is mature.

Voilà, that is all. The water is likely to be rather cloudy at first, even if you rinsed the substrate. The dust will settle and/or be cleared up by the filter within 24 hours or so, at which point you can admire your new masterpiece in its full splendor.

Don’t forget: you can’t immediately add fish to your new tank. It has to cycle for 3-4 weeks first, or any livestock you introduce will likely die off. If you’re not sure about what you should do next, have a look at our full post on the nitrogen cycle.

Conclusion

Setting up a brand-new aquarium is a pretty simple process, though larger tanks can take a while to fill up. No time or still not sure how to do it? Contact FantaSEA Aquariums and we’ll install your tank for you, so all you have to do is enjoy it!