Aquarium Decorations: What To and What Not To Add – Beginners Guide

Are you planning to have a pet fish but don’t know where to begin from? I can tell you’ve already been to the aquarium shop and got overwhelmed after seeing all the cute aquarium decor items. Sometimes we choose things that are appealing to our eyes but can be hazardous for our aquarium fish. You might not be aware of those things. That’s why you’ve clicked this article, didn’t you? Well, I would’ve done the same thing if I were in your shoes. You have chosen the right article to get some aquarium decorations ideas for your aquarium. Now let’s dive right into it.

Head Start on The Aquarium Decor

Oh! I can understand the dilemma while setting up the aquarium. You want to buy a plant, you also want to buy some accessories, but you don’t want to overcrowd your aquarium at the same time. Trust me; I’ve been there too. How I wish I knew those two basic things before setting up an aquarium. And by two basic things, I meant a good master plan and some preparation. Plan out all the essentials required for your aquarium. Do some research on your desired fish species, and then you can think about the size, shape, and location of your aquarium.

Just like soon to be mom and dad get everything ready for their unborn child, you have to set up everything before welcoming your pet fish. From the aquarium to fish food, make sure you’ve all the stuff with you beforehand. Plus, don’t forget about your budget too.

Choose The Deserving Aquarium For Your Fish

Now that your homework on your desired fish species is done, it’s time to do all the necessary preparations. Remember, you’re about to take responsibility for keeping living beings alive. So, make sure to do it in your best possible way. In return, you’ll achieve numerous benefits from your darling fish.

Read More: 20 Health Benefits of Keeping an Aquarium Fish At Home Or Office

Start from choosing the masterpiece for your home i.e., the aquarium. The size of your aquarium depends on the type and number of fish that you’re planning to have. You can have different types of freshwater aquariums to choose from. Don’t go too overboard. Select the one that is suitable for your fish and is budget-friendly.

Choose An Ideal Location 

Newbies! Choosing the right location for your aquarium is an important decision, both scientifically and spiritually. Of course, you don’t want your beloved fish to get health issues, right? So, take your time to select the ideal location for your aquarium. I agree that looking for the right size of a high-quality aquarium is equally essential, but the location plays the lead role here. This is because the location influences your behavior as well as that of your fish. Here are some tips to have in mind while selecting the location.

  • Keep your aquarium someplace where it can be noticed and admired easily, not in the way where you need to take someone into it.
  • Place your aquarium somewhere spacious so that you can feed and perform maintenance tasks without bumping into something.
  • Do not place your aquarium near a window or direct sunlight. A small amount of natural sunlight on your aquarium is good, but direct sunlight alters the water temperature and causes excessive growth of algae.
  • Do not put your aquarium near a heating or cooling event as this will also cause fluctuation in the temperature of aquarium water.

Also, if you’re a believer in Vastu Shastra or Feng Shui, place the aquarium in accordance with those principles. Now, you’re ready to set up your aquarium.

The Bottom-Up Aquarium Decor Setup

Aquarium decor starts from the base; henceforth, you can call it the bottom-up setup: sand or glass pebbles or gravel, or stones. Choose any substrate to layer the base of your aquarium. It’s up to you. If you want to create a planted aquarium, then you’ll have to choose the substrate accordingly. Just make sure that your taste in the substrate considers the four aspects: reaction with the water, effects on your fish, particle size, and color.

Substrate enhances the look of the aquarium. If you’re into aesthetic design, you’ll choose the mild colors, and if you’re on the colorful side, you’ll want a pop of colors in your substrate as well. Either way, you’re letting your fish shine in the aquarium. Also, your fish will have a sense of their natural habitat with the substrate.

Clean the aquarium with only warm water to remove all the toxic chemicals and residues. While pouring water, check if there is any leakage. Rinse your desired substrate with warm water as well to get all of the debris out. Place the aquarium at the ideal location that you’ve chosen. You won’t be able to shift the aquarium after filling the substrate, so it’s better to move it before filling.

Now, pour some base fertilizers if you’re planning to grow plants. One lb of the substrate is thick enough for one gallon of water. Add the substrate in such a way that it creates a slope towards the back of your aquarium. After filling the aquarium with the substrate, slowly pour fresh water using a saucer or a bowl to prevent from ruining the base. Then drop some de-chlorinator as per the instructions to the water.


Before moving on with the aquarium decor, you have some installations to do. The basic types of equipment you require for your aquarium are a filter, heater, and a thermometer. Install the equipment following the instructions given in the box, or you can watch a YouTube tutorial on your brand of filter, heater, and thermometer.

Fix the heater and the thermometer on opposite sides of your aquarium. By doing so, you will know if the whole aquarium is evenly heated or not. Check whether each equipment is properly installed before turning it on at the power supply. Turn them on and allow the setup to stabilize for 2-3 days.

Time For Aquarium Decor

Finally, the time has come to decorate your aquarium. You can decorate the aquarium exactly how you imagined it to be. When it comes to aquarium decor, anything is possible. Is it a cartoon theme? Or is it a Disney theme? You name it, you’ll get it at your nearby pet store.

The decor items are specially designed for fish tanks so they won’t dissolve in water. Decorate your aquarium in such a way that your fish can have an ample amount of space to roam around it. Also, choose the items that don’t poke your fish here and there every time they glide around.

If you’re planning to add some plants in the aquarium, then I’d suggest you buy real plants over fake ones. Why? Even though the fake plant is much more vivid and easy to maintain, there’s no way it can beat the creation of nature. Real plants use your fish’s feces to absorb nitrogen; thus, improving the water quality of your aquarium. Plants maintain the pH level of the water by using carbon dioxide and giving off oxygen. What do you prefer now?

Every single one of us wants our aquarium to look unique. Sometimes this makes us think out of the box, and we’re tempted to add some items in the aquarium that we never should. This will eventually harm our fish, which we don’t want to happen even in our nightmares. Don’t worry. Keep reading this article to find all the list of items that aren’t designed to go into the aquarium.

Welcome Your Fish

After the decoration is completed, leave the aquarium to stabilize again for two days. After two days, check the temperature and pH level of the aquarium water using the water test-kits. Although you’re introducing your fish to their forever home, it’s completely new for them in comparison to their natural habitat. So, the testing will reduce the stress on your naive fish.

Be gentle while transferring them to your aquarium. Never mix the water from the plastic bag with the aquarium water unless you want to contaminate it. Don’t feed the fish immediately. Let them adapt to their new home for a day.

Things You Must Never Put In Your Aquarium

Home sweet home! There’s nothing more important than a good, safe, secure home. The same goes for your lovely fish. The aquarium should be a haven for your fish. You must create a healthy environment for the well-being of your fish. You must be careful while putting accessories in your aquarium.

Think about it. The things that you put for the sake of your eyes can be life-threatening for your fish. I won’t say that putting certain things in the aquarium can kill your fish at once. However, they are as worst as intentionally putting harmful chemicals in the aquarium water. You wouldn’t want that, would you? Here’s the list of things you must never put in your aquarium.

Things To Avoid


Plastics Release toxic chemicals when submerged in water
Coins Release copper and poison water
Electronics High chances of electrical injury
Ceramics Release terra-cotta clay and lead in water
Untreated Woods Spread infections and diseases
Sharp Objects Prone to cuts and bruises
Toxic Chemicals Cause severe skin diseases
Thorny Plants Injure fish internally and externally
Beach Sand Contains toxins
Wrong Fish Breeds Disturbs the ambiance and even deaths of fish
Wrong Type of Fish Food Obesity or constipation in fish
Untreated Rocks & Gravels Cause fungal and bacterial infections in fish
Rottable Things Contaminate water
Corals & Oysters Imbalance pH level and hardens the water
Soft Toys Pollute aquarium water
Your Hands Prone to germs and bacteria

Let’s know why these items are unsafe for your aquarium fish in detail.

Plastic As an Aquarium Decor

Don’t ever put objects made out of plastic in your aquarium. We are already polluting our environment using plastics in the first place, so why would you further want to pollute your aquarium?

Painted plastic toys release toxic chemicals when submerged in the water and can cause various infections if your fish chew or even lick them. Putting plastics in the aquarium simply means one thing; you’re intentionally putting your fish on their deathbed.


Everybody wants their wish to get fulfilled, but that doesn’t mean you’ll start throwing coins in your aquarium too. The fountains that you throw coins at are cleaned every day by the workers, so it is okay to wish for good luck there. Your coins might help someone in need.

Let me repeat. Don’t throw coins into your aquarium for whatever reason. The copper coin may be good to look at from outside, but it is very dangerous for your fish. Copper or any metal object poisons the aquarium water by releasing toxic chemicals, and I guess you can already imagine the result. Why don’t you keep the coins in a coin collection book instead and let your fish live in a clean environment?


Don’t submerge any electronics such as light, batteries, and sound devices in the aquarium water. As you know that electronics and water don’t go well together, there are high chances of your fish getting accidental death due to electric shock and short circuits. Also, batteries rust in water and release poison, which is equally life-threatening for your fish.


Fish love to hang out at the hiding places, but ceramic isn’t the option. Ceramics are made of terra-cotta clay and lead, which easily wear-off when immersed in the water. Licking or chewing ceramics can be the cause of loss of wings, color fade, poisoning, diseases, and death of your fish. So what if you can’t keep ceramics in your aquarium? You can still add those adorable mini-caves or mini-wooden houses in your aquarium.

Untreated Wood As an Aquarium Decor

Untreated, unsafe, unshaped, hard, crude, and decomposed woods are big no-nos for your aquarium. These woods are prone to injure and spread infections and diseases in fish.

Untreated Rocks & Gravels

Untreated rocks and gravels can be the cause of fungal and bacterial infections in your fish. Wash them thoroughly before putting them in the aquarium. Don’t throw the rock directly into your aquarium as it might bruise your fish.

Sharp Objects

Apart from children, fish also do justice to the phrase, “Keep away from children.” If you don’t want your water babies from having cuts and bruises on their tender bodies, avoid putting sharp objects like pointed glass, rocks, gravels, and decoration at the bottom of your aquarium because it hurts more to see blood on your darling pets than on yourself, isn’t it?

Toxic Chemicals

I’ve seen some people adding preservatives and chemicals in hopes of cleaning aquarium water. It’s not okay. If the smell of chemicals can disturb fish breed and cause severe skin diseases in fish, then imagine what will the poisonous liquids do to their bodies. Don’t let your laziness be the reason for your fish’s suffering and untimely death. Break out of your laziness cycle and change your aquarium water thrice a week.

Soft Toy As an Aquarium Decor

Soft toys can be washed yet can’t be submerged in the aquarium. Plushy toys are made for human babies, not for your fish. It’s just like soaking clothes in water for a long time. The color will dissolve in the water, and the foul smell of the fabric will cause hazardous diseases in your fish. Why don’t you keep those plushies for yourself?

Thorny Plant As an Aquarium Decor

Although thorny plants look good in the aquarium from our perspective, they can injure your fish both internally and externally. Fish aren’t cautious like us, so they glide anywhere without being careful. Don’t keep any pricky plants at all, and your fish won’t get hurt.

Beach Sand As Substrate

Natural beach sand is fine for the oceans and seas, and fish can handle it in their natural environment. However, that’s not the case for your aquarium. Beach sand is polluted, but the oceans and seas renew it naturally. Do you think your at-home aquarium water can do that? Not.

I know gazing at the beach sand in your aquarium gives you a sensation of being at the beach. Think about the chemicals in it. Your fish can’t handle those toxins of the beach sand. Don’t be sad. You can put treated dupes for sand that is a great substrate for your fish.

Livestock To Avoid in Freshwater Aquarium

Incompatible Fish

It’s said that a small aquarium is easy to keep and maintain. But, what if the fish that you’re planning to buy is larger than the aquarium? Fish should neither be large nor of the same size as your aquarium. Your water babies won’t be able to move freely and would get stressed in a congested aquarium. Check the size of the fish and choose the ones that are compatible with your aquarium.

Read More: How To Setup A 20-Gallon Fish Tank: Livestock and Equipment List

Wrong Fish Breeds 

Would you be able to live your entire life with your enemy in the same room? You can’t even imagine it. Putting the wrong kind of fish breeds in the aquarium is like keeping enemies in the same room. Compatibility matters in fish species as well. Don’t ever make the mistake of keeping aggressive fish with peaceful fish or large fish breeds with the tiny ones. Because if you do that, you’ll have to witness fights, bloodsheds, and the death of your fish.

Sea Creatures

Never put seawater creatures in your freshwater aquarium. Also, don’t put freshwater fish and seawater creatures together in one aquarium. Firstly, you won’t be able to create a perfect environment for both species, and secondly, this will only stress out your fish. Because of the disturbance in their atmosphere, there will be a high chance of their death.

Sea Shells, Corals & Oysters As Aquarium Decor Items

Corals, shells, and oysters are found in seas and are perfect to put in saltwater aquariums. However, these decor items are not suitable for your aerated freshwater aquarium as they have their pH level and hardness that don’t match with the freshwater. Don’t disturb your fish’s peaceful environment by putting these items.

Read More: Maintain Aquarium Water Hardness – Freshwater Aquarium Guide

Other Things To Avoid in Your Aquarium

Few other things can be dangerous for your freshwater aquarium fish. Now, I wouldn’t say that putting these things in your aquarium will affect your fish immediately. But, it’s better to avoid it beforehand than bear the consequences later. Right?

Wrong Type of Fish Food

Novice aquarists often make the mistake of sprinkling the wrong type of fish food in the aquarium. Fish tend to eat anything and everything that’s given to them. Consuming low-quality fish food can be a slow poison for your fish and can make them obese or constipated. Of course, you want the best for your pet fish, and you did it unintentionally. It’s not your fault. Next time when you go to the pet store, do not choose the fish food that has the following ingredients.

Read More: Obesity in Aquarium Fish: Are You Overfeeding Your Fish?

Ingredients to Avoid in Fish Food

  • Wheat flour
  • Starches
  • Potato protein
  • Soybean meal
  • Sorbitol

Rottable Things

Decomposable objects are a disgrace for your aquarium decor. Avoid feeding anything such as dead shrimps and worms that decompose easily in the water. Dead and decaying animals might be cheap, but these foods severely affect your fish’s immune system. You can always opt for home-made fish foods if you want to save money.

Read More: Can Fish Eat Human Food: What Are They And How To Prepare Them?

Your Hands

Wash your hands properly before dipping them in the aquarium. Our hands are the home for germs and bacteria, so, rinse your hands with mild hand soap before feeding or shifting your fish from one aquarium to another.

Water Sources That Aren’t Ideal For Your Aquarium

Water is a lifeline for all of us, but your fish, it’s indispensable. The lives of aquatic creatures survive on it. As for the well-being of your fish, you must know which water source is best for your aquarium. The following water sources aren’t ideal for your freshwater aquarium.

Well Water

Unlike tap water, well water isn’t tested by the government. Although the well water is chlorine-free, it can be hard or soft depending on the country you live in. The levels of mineral content and pH are unknown. Thus, well water isn’t good for your freshwater fish.

Rain Water

I wouldn’t recommend this source because you’ll have to make a lot of adjustments with rainwater to make it suitable for your fish. Rainwater has a low pH level and almost zero minerals. Besides that, rainfall isn’t frequent in many parts of the world. Plus, think about the impurities that come with the rainwater.

Collected Water

Water collected from your nearby stream or lake can be used for your aquarium but, it is quite similar to rainwater. Like I mentioned before, nature has its way of changing the conditions. Don’t compare the stream with your aquarium as they are a completely different environment. Also, you’ll have to carry water from the stream frequently and deal with fungi, bacteria, viruses, and parasites.

Things You Can Put In Your Freshwater Aquarium

You might have been clear about the things to avoid in your aquarium by now. However, you’re still unaware of the things that you can keep in your aquarium. You might be wondering what’s there to put in your aquarium when all the items you’ve thought about are mentioned in the “things to avoid list.”

There are some things that you can put in your freshwater aquarium without any worries. These items are safe for your fish and will also make your aquarium look astonishing.


Plants are the best decor items to put in your aquarium. They make your aquarium look bright and lively. The real plants filter the water naturally to keep your fish healthy. Moreover, green plants can help in breeding small fish. Ask for plants like Amazon Sword, Java Moss, dwarf lilies, and Java Fern to keep in your aquarium. You can also opt for fake plants, but these aren’t beneficial like real plants. So, I would prefer real plants over fake ones.

Clean Woods

Sterilized woods are great for your fish. You can decorate your aquarium with a finely shaped wooden house. It’s like a home inside a home for your fish. Driftwood is safe to keep in your aquarium. Also, this decor item has a 2-in-1 offer for your fish. They can hide as well as enjoy having those algae on the driftwood.

Special Sands

As you already know, you can’t put beach sand in the aquarium. The good news is you can use sterilized and non-toxic sands specially made for putting in the aquarium. These sands look exactly like beach sands and are available in different colors.

Non-Toxic Rocks & Gravels

Non-toxic rocks and gravels should be washed thoroughly before putting in the aquarium. For freshwater fish, rocks with low calcium are suitable. Quartz, lava rocks, basalt rocks, shale, and slate are great for your aquarium. Plus, your aquarium will look ten times better with these rocks.


You can’t fix the electronics in your aquarium. Instead, you can fix beautiful lightings at the ceiling of the aquarium for that additional beauty.

Ideal Water Sources For Your Aquarium

Fish can survive in the seawater somehow because nature has its ways of improving. There’s a huge difference between natural habitat and your aquarium. As an aquarist, it’s your responsibility to make the adjustments for your lovely fish. So, it’s better to have a water test kit to check these levels and make the necessary improvements. Here are the different sources of water that are ideal for your freshwater aquarium.

Tap Water

The cheapest source of water is tap water. This easily available water is just a few steps away from you. Turn your faucet on, fill your aquarium and your fish will do quite well in it. Tap water has chlorine in it that kills bacteria, making it safe for us to drink. Nonetheless, your aquarium needs good bacteria. Simply, dechlorinate the tap water.

Distilled Water

Distilled water is an affordable option that comes for under a dollar per gallon. This bacteria and chemical-free water is easily available at the grocery store near you and is perfect for filling mini-aquariums. Distilled water is also free of minerals, so; you’ll need to remineralize it before pouring into your aquarium.

Reverse Osmosis Water

Many of you might have the Reverse Osmosis (RO) system fixed under your sink that can remove 90-99% contaminants from water. It’s necessary to have minerals in the water to maintain the pH level and osmoregulation in your fish. So, if you think of using RO water in your aquarium, add re-mineralizer to restore minerals.

De-Ionized (DI) Water

De-Ionization is slightly different from the RO system; still, the functions are similar. With chemical resin-filled filters, this system purifies water by removing not only minerals but also artificial chemicals like pesticides. So, it has the potential to filter out 5-10% more impurities than the RO system.

RO/DI Water

If the RO system and DI system separately can filter out so many contaminants individually, imagine what both systems do together. You can combine both the Reverse Osmosis and the De-Ionization systems in a single device, and the combination will yield the purest form of water. You’ll have to remineralize the water though.

Softened Water

If you have a home water softener and want to use the softened water for your aquarium, then confirm the water’s safety with its manufacturer and aquarists before pouring it in your aquarium.

Aquarium Decor Cleaning Hacks

We, the couch potatoes, don’t like to clean our room that often. But alas, we must clean the aquarium frequently for our fish’s welfare. Don’t worry. It’s super simple to clean the aquarium.

Substrate Wash

Shift your fish with fishnet to a clean bucket full of aerated water. This will allow you to clean the entire aquarium properly. Remove the dirty water from the aquarium using a water siphon vacuum. Take out the aquarium decor items and clean them separately. Wash the rocks and gravels thoroughly.

Scrub off

Mix a mild liquid soap, vinegar, bleach, and lemon to clean your aquarium. Use a scraper to scrub off all the stubborn algae, dirt, and decomposed things. Rub every nooks and corner of your aquarium and make it shine like a diamond. Rinse it off with clean water.

Cleansing Filter

Use the same cleaning mix to rub off the dirt from the aquarium filter. No one has the time and money to replace it every week. You have to keep it in the long run. Clean the filter fiber, ceramic rings, and tubing of the filter with a filter brush. Dry the filter with a clean towel.

Water Change

Change the water twice a week. Do the water test, dechlorinate, and remineralize if necessary.

More About Aquarium Decor

Why Should I Decorate My Aquarium?

The aquarium is like a gem for your room. Decorating your aquarium is beneficial for you and your fish. It’s a fun thing to do. Aquarium decor creates a home-like atmosphere for your fish. It is something that you can admire when you come home after a long tiring day.

Can I Add Background To My Aquarium?

YES! You can add a background in your aquarium. This will enhance the color of your fish. Fish won’t be able to see their reflection, thus, reducing stress. The black backdrop makes your fish stand out in the aquarium. Also, a darker shade of blue backdrop gives a marine vibe. A picture of a palace as a background would look lovely too.

Can I Use Household Items As Aquarium Decor?

Household items are usually made of ceramics, plastics, metals, and clays. So, it’s better to buy decor items from the pet store that are specially designed for the aquarium.

Can I Boil Rocks And Driftwoods?

A great way of sanitizing decor items is by boiling them. Bring water to a full boil and put the rocks and driftwoods in it. Just 5-10 minutes of boiling the driftwoods are enough to kill germs. As for the rocks, you need to boil them for about 30 minutes.

Make Your Aquarium Interesting With Aquarium Decor

Metaphorically speaking, the aquarium is an empty canvas for you, and you’re the artist. You already have nature’s aesthetic creation with you. All you need to do is to use your creativity and fill the canvas. Bring your imagination to life using aquarium decor items and let the admirers say WOW to your masterpiece.


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