What Can I Put In A Fish Tank – ? The Ultimate Guide To Safe And Stunn
Have you ever stared at an empty glass box and felt a mix of total excitement and absolute overwhelm? You are not alone! Choosing what can i put in a fish tank is arguably the most rewarding part of the hobby, but it is also where most mistakes happen.
I understand that you want a vibrant, healthy ecosystem that doesn’t just look good but actually thrives. Whether you are a beginner looking for your first goldfish or an intermediate keeper branching into shrimp, I’ve got your back.
In this guide, I will walk you through the best livestock, plants, and hardscape materials. We will also cover the dangerous items you must avoid at all costs to keep your aquatic friends safe.
Choosing the Right Substrate: The Foundation of Your Tank
Before we talk about the “stars of the show,” we need to discuss the floor. The substrate is more than just “dirt”; it is a biological filter and a home for beneficial bacteria.
When considering what can i put in a fish tank as a base, you generally have three main choices: gravel, sand, or specialized plant soil.
Smooth Aquarium Gravel
Gravel is the classic choice for beginners. It is easy to clean with a siphon and comes in various sizes. I always recommend natural-colored, rounded gravel.
Avoid gravel with sharp edges, especially if you plan on keeping bottom-dwellers like Corydoras. Sharp stones can tear their delicate barbels (whiskers), leading to infections.
Inert Aquarium Sand
Sand is fantastic for a natural look and is a must-have for “sifters” like Cichlids or loaches. It prevents food from falling deep into the cracks where it can rot.
However, sand can compact over time. I suggest stirring the top layer occasionally or keeping Malaysian Trumpet Snails to help aerate the sand for you.
Active Soils for Planted Tanks
If your goal is a lush, green jungle, you should look into aquasoils. These are nutrient-rich pellets that help plants grow without needing immediate liquid fertilization.
Be aware that some active soils can lower your pH or release ammonia initially. Always test your water parameters before adding any fish to a tank with new aquasoil.
Live Animals: Beyond Just Fish
When people ask “what can i put in a fish tank,” they often forget that an aquarium can be a diverse community of many different species.
Mixing different types of inhabitants can create a balanced ecosystem where every creature has a specific job to do.
Peaceful Community Fish
For beginners, I always suggest starting with hardy, peaceful species. Neon Tetras, Zebra Danios, and Guppies are excellent choices.
These fish are forgiving of minor “newbie” mistakes and provide constant movement. Just remember to research their specific temperature and pH requirements before mixing them.
Freshwater Shrimp: The Tiny Janitors
I am a huge fan of Neocaridina shrimp (like Cherry Shrimp). They are incredibly fun to watch and spend their entire day eating algae and leftover fish food.
Shrimp have a very low bio-load, meaning they don’t produce much waste. This makes them a perfect addition to smaller “nano” tanks where space is a premium.
Ornamental Snails
Don’t let the word “snail” scare you! Species like Nerite Snails or Mystery Snails are beautiful and won’t overpopulate your tank like “pest” snails do.
Nerites are world-class algae eaters. They will keep your glass sparkling clean, though they do occasionally leave small white eggs on driftwood that can be tricky to scrub off.
Live Plants: Bringing the Jungle Indoors
Live plants are the secret weapon of successful aquarists. They absorb nitrates, provide oxygen, and give your fish a sense of security.
Don’t worry—you don’t need a “green thumb” to keep aquarium plants alive! There are plenty of options that are nearly impossible to kill.
Beginner-Friendly Epiphytes
Epiphytes are plants that grow on rocks or wood rather than in the soil. Anubias and Java Fern are the gold standard for beginners.
The most important rule: Do not bury their rhizome (the thick horizontal stem). If you bury it in the sand, the plant will rot. Simply tie or glue them to a piece of decor!
Floating Plants
If you want to manage algae, floating plants like Amazon Frogbit or Salvinia are incredible. They shade the tank and suck up nutrients directly from the water column.
Floating plants also provide a wonderful “canopy” for fish that like lower light. Bettas and Gouramis especially love lounging among the dangling roots.
Hardscape Materials: What Can I Put in a Fish Tank for Decoration?
Hardscape refers to the non-living elements like rocks and wood. This is where you can get creative and build a stunning underwater landscape.
When deciding what can i put in a fish tank for decor, safety is your primary concern. Not all “nature” is safe for an enclosed aquarium.
Aquarium-Safe Rocks
Popular choices include Dragon Stone (Ohko Stone) and Seiryu Stone. Dragon stone is inert, meaning it won’t change your water chemistry.
Seiryu stone, however, can slightly raise your pH and hardness. This is actually great for shrimp and livebearers but might not be ideal for soft-water fish like Discus.
Natural Driftwood
Adding wood to a tank adds instant character. Spider Wood and Mopani Wood are the most common types found in local fish stores.
Wood often releases tannins, which turn the water a light tea color. This is actually very healthy for fish, but if you dislike the look, you can boil the wood first.
Safe Artificial Decor
If you prefer “sunken ships” or “castles,” that is perfectly fine! Just ensure they are made of food-grade resin and have no sharp plastic edges.
I always recommend running a pair of pantyhose over any plastic decoration. If the fabric snags, it will likely tear your fish’s delicate fins as well.
Items You Should NEVER Put in a Fish Tank
This is the most critical part of the guide. Some items might look cool, but they can leach toxins that will wipe out your entire tank in hours.
Safety first! If you aren’t 100% sure about an item, it is better to leave it out or consult an expert.
Metals and Heavy Ores
Never put anything containing copper, lead, or iron into your tank. Over time, these metals oxidize and become highly toxic to fish and invertebrates.
Even some “decorative” stones found outside might contain metal veins. A quick way to test is the “vinegar test”—if a rock fizzes when you drop vinegar on it, it may change your water chemistry.
Unsealed Plastics and Toys
While some people put LEGOs in tanks, I generally advise against random plastic toys. Not all plastics are “aquarium safe” and may leach chemicals over time.
Stick to decorations specifically labeled for aquarium use. These are tested to ensure they don’t break down under constant UV light and water exposure.
Unprocessed Wood from Outside
It is tempting to grab a cool branch from the park, but this is risky. It could contain pesticides, parasites, or sap that is toxic to your fish.
Softwoods like pine or cedar are particularly dangerous because they contain resins that can kill fish. Always stick to hardwoods or store-bought aquarium wood.
How to Ensure Compatibility and Safety
Now that you have a list of what can i put in a fish tank, you need to make sure they all play nice together. An aquarium is a delicate balance.
Think of your tank like a small apartment. You wouldn’t want a roommate who eats your food and hits you, right? Fish feel the same way!
Managing the Bio-load
Every living thing produces waste. If you put too many animals in the tank, the beneficial bacteria won’t be able to keep up, leading to toxic ammonia spikes.
A good rule of thumb is to start slow. Add one or two fish, wait a week, test your water, and then add more if everything looks stable.
The “If it Fits in Their Mouth” Rule
In the fish world, most things are food. If you put a tiny shrimp in a tank with a large Angelfish, that shrimp will likely become an expensive snack.
Always check the maximum adult size of your fish. That cute 1-inch fish at the pet store might grow into a 10-inch monster that eats everything else!
Temperature and Water Parameters
Not all “tropical” fish like the same water. Some prefer cool water (68°F), while others need it quite warm (82°F).
Always group your inhabitants by their needs. Keeping a cold-water Goldfish with a heat-loving Betta is a recipe for stress and disease for both animals.
Frequently Asked Questions
Can I put sea shells in my freshwater tank?
You can, but be careful! Sea shells are made of calcium carbonate. They will slowly dissolve and raise the pH and hardness of your water. This is fine for African Cichlids but bad for Tetras.
Is it safe to put glass jars or bottles in a tank?
Generally, yes, as long as they are thoroughly cleaned and have no sharp edges. However, make sure there are no stickers or glue residue left on the glass, as these can be toxic.
Can I use “play sand” from a hardware store?
Yes, many hobbyists use pool filter sand or play sand because it’s cheap. However, you must rinse it extremely well. If you don’t, your tank will stay cloudy for weeks!
How many fish can I put in a 10-gallon tank?
There is no “one size fits all” answer, but for a 10-gallon, I recommend a small school of 6-8 nano fish (like Chili Rasboras) or a single Betta with some snails.
Do I need to boil driftwood before putting it in?
Boiling isn’t strictly necessary, but it helps. It kills any potential hitchhikers, helps the wood sink faster, and removes some of the brown tannins that discolor the water.
Conclusion: Building Your Perfect Underwater World
Figuring out what can i put in a fish tank is a journey of discovery. By choosing the right substrate, compatible animals, and safe decorations, you are setting yourself up for success.
Don’t feel pressured to have a “perfect” tank on day one. Most of the best aquariums I’ve ever seen were built slowly, piece by piece, as the owner learned what worked best for them.
Remember to prioritize the health of your livestock over aesthetics. A happy fish is a beautiful fish! If you stick to natural materials and research your species’ needs, you’ll have a thriving ecosystem in no time.
Happy fish keeping, and welcome to the wonderful world of Aquifarm! Feel free to reach out if you have more questions about your specific setup—we are always here to help.
