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A complete guide to aquarium essentials for first-time fish owners

You’re ready to dive into your first aquarium, but where do you start? Owning freshwater fish might seem easier than keeping other pets, but it still requires prep work and care. For starters, always purchase your tank, food, and equipment before heading into the pet store to pick up your new fish. This way, you’ll have everything ready to go (and the opportunity to troubleshoot any surprise problems). By setting yourself up in advance with aquarium essentials, you’ll conquer pet ownership with ease. 

Little girl feeds fish in her aquarium
Anatoly Tiplyashin/Shutterstock

What do I need to know before buying a fish tank?

Before you even purchase a tank, you’ll need to make a few key decisions — mainly which fish you get and how many. Getting too small a tank can hurt your fish and make it a lot harder to keep the environment clean. Some fish prefer to live together, like tetras, and others need to be alone, like bettas. Certain species might do fine together in theory but have vastly different temperature or lighting requirements, making it impractical to keep them in one tank.

We recommend true novices begin with a 20-gallon tank. While a couple of small fish can certainly live in a 10-gallon, it can actually be harder to maintain since it will get dirty faster. Remember, some of the worst offenders for your fish’s health are invisible to you, like ammonia and nitrates.

What else should I buy?

Your tank is just the beginning. Once you’ve selected the right size and have a good idea what types of fish you’ll be keeping, it’s time to look into accessories. Some of these are essentials and others are just fun. Start with a filter and other must-haves like a light or heating pad. Different species need different setups, and you’ll need to carefully pick instruments that fit your aquarium and space. While a solitary goldfish or betta might do all right without a filter, you’ll almost certainly need one for a larger group. If you’re adding a light source, a timer can make it easier on you, so you don’t need to remember one more light to turn off each day.

Next, you should grab fish food and other additives like aquarium conditioner, which helps keep the nutrients and chemicals in sync. A water-quality testing kit will be beneficial as well. Even with a filter, you’ll need to regularly wipe down some parts of the tank by hand and will want to deep-clean occasionally. Add pet-safe cleaning supplies to your list so you’re prepared when the time comes. Don’t forget replacement parts, a fish net, and fish medicine.

Last, but certainly not least, you get to pick out your decorations. Begin with the floor of your tank, which will probably be gravel or sand, and work your way up. Plants, ornaments, and toys will give your fish something to interact with or a place to hide. Live plants can be a great bonus to your new fish home but require extra maintenance. Stick with fake ones if this is your first try and level up as you go.

How do I set up my tank?

Make sure to put everything in your tank together, including water, before you bring home your new pet. For many fish, you’ll need to let the filter run for a few days or even longer to make the tank hospitable. Your fish need the proper oxygen and nutrients levels for them to thrive. Add all plants in advance, too, and keep an eye on them to ensure they take hold. Discard any dead plants or leaves immediately as those can disrupt the chemical balance of your mini ecosystem. 

If you have a water-testing kit, check the aquarium a few times at regular intervals while waiting for your new inhabitants. Also, examine your tank’s location at different times of day to check lighting and temperature. Fish are finicky, and you want to maintain a consistent habitat for them. 

You’re now ready to bring home your newest additions. Shop at a reputable store and examine your pets carefully before purchasing. Look for obvious signs of distress or sickness and poke around to confirm they’ve been kept in a big enough tank and are adequately fed. Once you get them home, they’ll need to acclimate to your water temperature before fully submerging. Last tip: Don’t go overboard buying every fish you’ve ever dreamed of owning. You can always get more, but too many will lead to fish congestion. We bet you’ll be an aquarium enthusiast in no time.

Rebekkah Adams
Rebekkah’s been a writer and editor for more than 10 years, both in print and digital. In addition to writing about pets…
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Fish tank with healthy bubbles coming out of filter

Where there's water, there are bubbles. It's unavoidable and you'll be chasing an impossible dream if you try to eliminate them from your aquarium entirely. For starters, the filter produces a continuous stream, and that's a good thing! It means the system works. But some bubbles may reveal underlying problems with your water or with your inhabitants. So, why are there bubbles in your fish tank, and how do you know if those little oxygen sacks indicate an issue or a healthy ecosystem? Here's how to tell where they're coming from and figure out what to do about it.
Why are there bubbles on plants?
Like we said, bubbles are often totally normal — no action required. This will especially hold true if you have live plants, which produce oxygen naturally and sometimes hold on to it in the form of bubbles. Of course, those eventually dissipate, at which point the gas inside seeps into the water. That's good! Fish need to breathe just like the rest of us and do so through their gills by pulling oxygen from the water in the tank. These types of bubbles go on the good to neutral list.

Why are there bubbles covering the surface?
So, what happens when there's not enough oxygen for your fish to function happily? When they can't get it from the water, they'll make their way to the surface and breathe the air. Some fish do this frequently, as do aquatic frogs and other non-fish aquarium dwellers, so don't take that act alone as an immediate cause for concern.

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You might know of rainbowfish from the beloved children's book, but these are real animals that you can keep in your own home. As the name suggests, this group of swimmers is well regarded for being beautiful to behold. Many also get along nicely with other fish and can be handled by beginners. This is what you need to know before bringing home a rainbowfish.
What are rainbow fish?
It's a bit of a catch-all term because there are at least 50 species that all fall under the rainbowfish umbrella. Some work better as pets than others, and you'll probably be looking at boesemani rainbowfish, turquoise rainbowfish, featherfin rainbowfish, or red neon rainbowfish. If you're adding to an existing tank, research carefully to ensure you only get ones that will make friends with your current animals.
What conditions do they need to live in?
These are all freshwater fish, but their exact temperature and pH balance needs vary depending on which species you bring home. You can use your existing tank specs to narrow it down or do the opposite — pick the prettiest fish and then build your ecosystem around it. One thing to note right away is that you shouldn't keep males together and no rainbowfish wants to live on its own because they like to school. Consider keeping a group of six females if you want to prevent expansion.

Why should you add them to your tank?
Here are four excellent reasons to keep rainbowfish as pets.
They look beautiful
You can find just about any gradient you want in a rainbowfish. Some incorporate many colors, more like a traditional rainbow, while others skew toward blue, such as the turquoise rainbowfish, or red, such as the aptly named red rainbowfish.
They get along with other fish
While you want them to have friends of their own species, they'll also do great with others. Female rainbowfish can sometimes live with female bettas if you want to create a color explosion. Otherwise consider catfish, gouramis, and loaches as tank mates.
They're good beginner fish
The care level of most rainbowfish sits at about the same as a neon tetra (in fact, they can live together). Make sure your tank stays clean and that you change and test the water frequently, but they don't have any specialty needs.
They live a long time
Many tank dwellers have short life spans, and rainbowfish won't be any different if not properly cared for. However, boesemani rainbowfish, in the right environment, regularly make it to 5 years and sometimes even t10 years!

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Two cory catfish hang out on the bottom of the tank

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What are corydoras?
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Are corydoras friendly?
Yes, corydoras are sweet and gentle fish. They particularly like spending time together, but get along with many others as well. In some cases, you should not buy just one as they'll get lonely. Instead grab a pair of the same type and watch them become best friends. You'll often see them as bottom feeders, well, at the base of the tank, but cory cats also come up to the surface for air or food from time to time.

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