Setting up an aquarium is more than just filling a tank with water and adding decorations; it’s about creating a safe, stable, and healthy environment for your fish and other aquatic life. However, not everything that looks beautiful or seems harmless belongs in an aquarium. These are twelve things that you should never put in your aquarium.
1. Untreated Wood
Untreated wood can be very harmful to an aquarium’s ecosystem because of its natural decomposition process. As it decomposes in the water, it will release tannins and organic compounds that can alter water chemistry, potentially causing pH fluctuations. Some types of wood also contain natural toxins or pesticides that can poison the water.
2. Beach Sand
While beach sand might seem safe to add to an aquarium, it can introduce several risks. Oftentimes, it contains contaminants such as microplastics, chemicals, and pollutants from ocean pollution, which can be harmful to aquatic life. It can also carry harmful bacteria, parasites, and microorganisms that could harm your fish.
3. Shells, Corals, and Ocean Rocks
While adding shells, corals, or ocean rocks to your aquarium might look nice, they can significantly affect water chemistry. They contain calcium carbonate, which will affect the pH level in your tank. These items should never be placed in freshwater tanks.
4. Cleaning Chemicals
Never use household cleaning products in or near your aquarium. These chemicals can destroy beneficial bacteria that are essential for maintaining water quality. Even small traces can be toxic to fish and could lead to illness or death.
5. Non-Aquarium Safe Plastics
Not all plastics are safe to use in an aquarium; some can leach harmful chemicals into the water over time. Plastics that are not specifically designed for aquariums can release substances like BPA or phthalates into the water, which can be toxic to fish. As they degrade over time, they could also release microplastics into the water, which fish might ingest.
6. Metallic Minerals or Ore-Bearing Rocks
Adding metallic minerals or ore-bearing rocks to your aquarium can pose serious risks. Many ores contain heavy metals like copper or zinc, which can leach into the water and poison fish. Some minerals can also alter the water’s pH levels, which can harm fish and invertebrates.
7. Mirrors Not Marked for Aquarium Use
Adding a regular mirror to your aquarium might seem like a good idea, but this can be problematic for many reasons. The backing of standard mirrors often contains toxic substances that can poison your fish. Broken mirror pieces can also injure fish or damage tank equipment. Only use mirrors that are marked for aquarium use.
8. Unsafe Ceramics
Some ceramics contain harmful substances like lead or copper that can leach into the water and harm aquatic life. Unglazed ceramics can also have porous surfaces that hold harmful bacteria, which can affect the water’s quality.
9. Limestone and Other Soft Rocks
Limestone and other soft rocks can alter the chemistry in water, which is why you should never add these rocks to your aquarium. They can raise pH levels, which can be harmful to fish. They can also increase water hardness by releasing calcium and other minerals.
10. Household Cleaning Sprays
Even indirect exposure to household cleaning sprays can be harmful to your aquarium. Aerosolized cleaning products can settle on the water surface and dissolve into the tank, poisoning fish and invertebrates. Never use any cleaning sprays close to your aquarium.
11. Wild-Caught Insects or Worms
Though feeding your fish wild-caught insects or worms might seem like a good idea, it can be very harmful. Many wild insects carry pesticides and other environmental toxins that can poison fish. They might also have parasites, which can infect the aquarium and spread diseases.
12. Brightly Colored Minerals and Crystals
Although colorful minerals and crystals may look nice in a fish tank, they can introduce toxic elements into your aquarium. Many blue and green minerals contain copper, which is highly toxic to invertebrates and some fish species. Always use aquarium-safe decorations in your tanks
