Things You Shouldn’t Put In An Aquarium

Things You Shouldn't Put In An Aquarium


Whether you’re a marine biology enthusiast, an aquarium hobbyist, or simply a wildlife lover yearning for a slice of life under the sea in your living room, knowing what to avoid in an aquarium is crucial. This guide will delve into the crux of this issue and explore the “Things You Shouldn’t Put In An Aquarium?”. This topic holds significant bearing, as it can mean the difference between fostering a thriving aquatic environment and witnessing a dismal fish-tank disaster.

Understanding What to Avoid In An Aquarium

Understanding what to avoid in a tank forms the linchpin of successful aquaculture. Your coveted aquarium can metamorphose into a thriving, vibrant, and healthy ecosystem or a hazardous death trap, contingent on what you put in a tank. This holds true across the vast spectrum of marine life – spanning freshwater and saltwater species- each having a unique set of requisites and tolerances.

Freshwater Species Dynamics

Freshwater fish hail from various ecosystems like rivers, lakes, and ponds, teeming with diverse forms of flora, fauna, and minerals. To mimic their native environments effectively, you need to know which elements are safe and which to avoid in a tank.

Saltwater Species Dynamics

On the other hand, saltwater species reside in oceans and seas across the globe, environments profoundly disparate from their freshwater counterparts. Consequently, the elements to shun or to put in a tank can vary significantly, underscoring the pressing need to understand these intricacies.

By acquiring a grasp of what should be avoided, you would set a sturdy foundation towards creating a flourishing aquarium that would be a joy to behold and a haven for your aquatic pets. Stick with us as we delve deeper into the technical aspects of things you should never put in a tank in the upcoming sections.

Technical Aspects of Things You Shouldn’t Put In An Aquarium

The things you put in a tank have profound impacts on the health and well-being of your aquatic pets. A careful consideration of the technical aspects offers a greater perspective of what to avoid in a tank.

Chemical Additives

Chemical additives found in decorations, cleaning detergents, and other substances may leach harmful substances into the water, affecting water’s chemistry and ultimately, the aquatic organisms’ health. Ensuring decorations, substrates, or fixtures are aquarium-safe is essential.

Incompatible Species

Not all fish species get along. Some are territorial or predatory. Introducing incompatible species to your tank could lead to conflicts, stress, or even fatality. Researching on species compatibility before adding fish to the tank should never be overlooked.

Ensuring a Safe Aquarium Environment

Aside from knowing what to avoid in a tank, understanding the optimal conditions of this protected ecosystem is also critical. These include the right water temperature, pH levels, and other elements that could influence what you put in a tank.

Water Temperature

Fish are poikilothermic animals, meaning that their body temperature varies depending on the water temperature. Each fish species has specific temperature requirements. Placing a heater in a tank unsuitable for tropical species or failing to provide a cooler for cold-water fish are things to avoid in a tank.

pH Levels and Other Water Parameters

Water parameters, including pH, hardness, and nitrate levels, impact the health of your aquarium inhabitants significantly. Using untreated tap water or failing to test and adjust these parameters periodically can endanger your aquatic pets’ health and stability of the aqua environment.

But knowing what things to avoid in a tank is just the start. Up next, we provide step-by-step procedures and precautions to guide you on managing and developing a successful and safe aquarium. Stay tuned.

Steps to Create a Safe Aquarium Environment

Understanding what to put in a tank encompasses acknowledging how to adequetly manage and develop a safe marine environment. Here are some tips to assist you:

  1. Ensure Suitability of Aquarium Decorations: Verify whether additions like ornaments, pebbles, rocks, and artificial plants are safe for the aquarium and non-toxic to the fish.
  2. Maintain Water Quality: Regularly check on parameters like pH, temperature, and nitrate levels. Ensure that they are in the ideal range for your aquatic species.
  3. Avoid Overcrowding: Only bring in fish that are compatible with one another and abstain from overpopulating the tank.
  4. Avoid Using Tap Water Without Treatment: Tap water often contains chlorine and other chemicals potentially harmful to aquatic life. Treat water appropriately before using it in your tank.

Remember, the key to a healthy tank lies in the proactive steps you take to prevent issues from happening.

Common things to avoid in a tankReason for AvoidingImpact on Freshwater SpeciesImpact on Saltwater Species
Untreated Tap WaterContains chlorine and other harmful substancesAlters pH and hardness levels, leading to stress among fishChallenges delicate water chemistry resulting in health issues
Unquarantined New FishPotential carriers of diseasesCan lead to disease outbreaks impacting the entire populationRisks of parasite introduction and widespread diseases
OverfeedingCauses water contamination and fish health issuesMight lead to bloating, constipation, and a lower immune response in fishSimilarly, leads to health complications and potential death
Incompatible Fish SpeciesLeads to stress, conflict, and potential fatalitiesAggression or territorial disputes might lead to a hostile tank environmentPredatory or incompatible species can decimate the whole population
Chemical Additive DecorationsCould leach toxins into the waterMay affect water chemistry, posing health risks to fish and other inhabitantsCan drastically upset the complex chemistry of saltwater tanks

Common Issues and Their Solutions

Despite the best efforts, problems in maintaining an aquarium are unsettling, yet not uncommon. Tackling them head-on using the correct measures ensures to avoid in a tank unwarranted scenarios.

Disease Outbreaks

Sometimes, new fish may bring in diseases into the tank. Quarantining new fish before officially introducing them to the tank could prevent disease outbreaks.

Algae Overgrowth

Not only does algae growth degrade the aesthetic appeal of your aquarium, but it can also deplete oxygen levels, creating an inhospitable environment for your aquatic inhabitants. Limit lighting to avoid excessive algae growth and incorporate algae-eating organisms to control this.

Inappropriate Water Conditions

Changes in water parameters can make fish susceptible to disease or even result in death. These could be due to inappropriate things you put in a tank, unpredictable temperature fluctuations, or an overabundance of fish waste. Regular monitoring and adjusting of water conditions can keep the disaster at bay.

The problems can be numerous, but they can be nipped in the bud with the right knowledge and equipment. Following these guidelines will not only avert potential hazards, but it will also steer your aquarium ambitions in the right direction. In the following sections, we dive into routine maintenance procedures and the impactful role this plays on your aquarium health. Stay tuned.

Routine Maintenance Practices

Knowledge about things to avoid in a tank serves as a fundamental brick in aquarium care, but maintaining routine practices cements your success. Here are a few tips for this integral part of the journey:

  1. Regular Water Changes: Execute small, frequent water changes rather than large overhauls. This keeps your aquarium’s water parameters in check while minimizing stress for the inhabitants.
  2. Equipment Check: Regularly inspect equipment like filters, heaters, and lights for any signs of dysfunction.
  3. Aquascaping Maintenance: Prune plants, remove dying leaves, and rearrange decorations periodically to create an environment conducive to fish health.

The Key to Success

Regular maintenance reduces the incidence of fish stress, disease, and mortality. It preserves the beauty and health of your aquarium, ensuring the well-being of your aquatic inhabitants.

Impact on Aquarium Ecosystem

Making informed choices on what to put in a tank and what to avoid in a tank has profound implications on your aquarium ecosystem. It all ties back to the balance of your closed aquatic system.

Freshwater Impact

For freshwater aquariums, inappropriate additions can drastically alter the pH levels and hardness of the water. This could trigger a domino effect, shaking up the gentle balance of your aquarium and adversely affecting the fish, plants, and microorganisms living within.

Saltwater Impact

In contrast, saltwater aquariums comprise more complicated water chemistry. Introducing elements that might be harmless in a freshwater set-up could lead to calamitous consequences in a saltwater system.

In perceiving the larger picture, each decision you make on what to avoid in an aquarium affects your tiny slice of the ocean or freshwater environment. In the next section, we’ll share advanced tips and best practices to help you achieve maximum optimal results with your aquarium. So stay tuned!

Advanced Tips and Good Practices

Getting to grips with things to avoid in an aquarium is only one side of the coin. You also need some advanced tips and good practices to ensure the long-term success of your hobby.

  1. Consider Your Fish’s Biotope: Do research on each species’ natural habitat and aim to mimic it in your tank. This can give the fish a more comfortable and familiar environment.
  2. Practice Patience: A healthy aquarium isn’t built in a day. Give your tank time to cycle before adding fish. Rushing this process can lead to avoidable problems.
  3. Invest in Quality Equipment: Bargains aren’t always the best deals when it comes to aquarium equipment. Opt for reliable, tested brands that promise durability and performance.
  4. Stay Informed: Keep learning about the latest trends, research, and guidelines in aquarium-keeping.

Armed with this knowledge, the chances of making a wrong decision on what to put in a tank is reduced, translating into a charming and thriving aquarium that both you and your aquatic inhabitants will love.


In conclusion, understanding the “Things You Shouldn’t Put In An Aquarium?” is crucial for every aquarist. Our ultimate goal is to create a tiny piece of the great blue seas or lively rivers in a confined space. This mission is rewarding, yet challenging, requiring constant learning, observation, and hard work. Every element you put in a tank plays a role in the grand scheme of things. Every pebble, decoration, or fish enhances or disrupts the equilibrium of your well-crafted ecosystem.

By avoiding the wrong choices, you directly ensure the welfare of your aquatic pets, the beauty of your tank, and ultimately, the success of your hobby. Remember, a thriving aquarium starts with a well-informed aquarist – and staying in-the-know on what to avoid in an aquarium leads to healthier, happier fish. Happy fish keeping!

Frequently Asked Questions

In this final section, let’s look into some frequently asked questions about the “Things You Shouldn’t Put In An Aquarium?” to help clarify common questions for beginners and seasoned aquarium enthusiasts alike.

Why Can’t I Just Use Any Tap Water in My Aquarium?

Tap water usually contains chlorine or chloramines, which are harmful to fish. Untreated tap water is something to avoid in a tank. To make it safe, use a good quality water conditioner before introducing tap water into your aquarium.

Can I Put any Household Objects as Decorations in My Aquarium?

Not all types of household items are safe to put in a tank. Items made of copper, or any object with paint, varnish, or a metallic finish should be avoided. They can leach harmful substances into the water. Go for decorations labelled as ‘aquarium safe’.

Why Do I Have to Avoid Certain Species of Fish in My Aquarium?

Every fish species has a unique temperament, size, diet, and water parameter requirements. Certain species can be predatory or territorial and may not get along in the same tank, causing stress or even death. Before adding a new fish, research species compatibility thoroughly.

Why is Overfeeding Harmful for My Aquarium?

Overfeeding impacts water quality, leading to an increase in nitrate levels and decrease in oxygen availability, making it a thing to avoid in an aquarium. It can also cause health issues in fish like bloating and constipation.

How Does an Unmaintained Filter Impact My Aquarium?

An unmaintained filter can get clogged or stop working altogether. This can lead to an accumulation of harmful substances in the water, disrupting the cycle of breaking down waste and depriving your aquarium of crucial filtration.

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