The Complete Beginner’s Guide to Goldfish

When my daughter brought home two goldfish from a local fair a few years ago, I had absolutely no idea what to do with our new pets. I had never kept fish before, and I didn’t know much about goldfish other than they seemed to love living in bowls.

So off to the local pet store I went, where on the advice of an employee, I purchased a 0.5-gallon (1.8 liter) plastic aquarium, a bottle of goldfish food, and a cute little net.

Needless to say, things didn’t go too well. One of the goldfish died before the end of the week, leaving my young daughter devastated. Even worse, the other goldfish didn’t look too healthy and I resolved to not let anything happen to Gorby (my husband named the white goldfish after a certain Soviet leader for the red spot on its head).

Determined to keep the other goldfish alive, I devoured every article I could find online and quickly realized I was doing nearly everything wrong. Looking back, it was a miracle Gorby had lasted as long as he did in my inexperienced hands.

But armed with my new knowledge, I felt ready to take care of my daughter’s goldfish. And now I can share everything I learned to help other people avoid making the same mistakes I did.

Please, Please Don’t Buy a Goldfish Bowl

The first thing I did wrong was to listen to the employee at the local pet store. No matter what someone tells you, goldfish don’t like fishbowls. Which I find a bit weird, since the bowls are literally named after them, but I can’t stress this enough: do not buy a fishbowl for your goldfish.

Goldfish can grow incredibly large if you take care of them properly. Some can grow to a massive 18 inches long – yes, you heard me right. 18 inches! And most goldfish will live for more than 10 years, with one record-holding goldfish surviving an amazing 43 years.

But if you can’t use a goldfish bowl, what should you keep goldfish in? The answer is you need to keep goldfish in an aquarium. And not a small aquarium either. Goldfish produce a lot of waste (they go to the washroom almost non-stop in their aquariums) and things will get unpleasant quickly if they don’t have enough room.

If the fish are really young, you could probably keep one or two goldfish in a 10-gallon aquarium, but things are going to be tight in there. I suggest most people start with a 29-gallon aquarium, especially if you buy one of the fancy goldfish that stay a bit smaller. If you buy a comet or common goldfish, be prepared to purchase at least a 55-gallon aquarium. Comets and common goldfish grow absolutely massive.

Setting up Your Aquarium

Now that you’ve ignored the goldfish bowls at the pet store and bought a proper aquarium for your goldfish, you need to set it up. The good news is the setup is pretty easy.

There are a lot of fish out there who are very picky about temperature, water hardness, and tank setup, but goldfish are so hardy and adaptable they don’t really care about any of those things. They’re pretty happy being plopped down in almost any water conditions.

Still, you’re going to need the basics. First, you need to buy a substrate for the bottom of the tank. The two best options are aquarium safe gravel and play sand. A lot of people prefer sand since goldfish love digging around in it, but if you don’t want the extra hassle of sand, gravel is still a great choice.

Next, you’re going to need to pick up a filter for your aquarium. Remember when I said goldfish go to the washroom almost non-stop in their aquariums? You need a strong filter to deal with that. The filter helps to clean out the goldfish waste and keep the water in good condition. If you don’t keep the water clean with a filter, it can quickly turn toxic and hurt your goldfish. And no one wants that.

If you’re going to buy a filter, the writers at Aquarium Tidings agree the AquaClear Power Filter is one of the best filters you can own. It’s really easy to use and usually lasts for years without any problems. I bought one for my first tank and it’s still going strong.

And finally, after you have the filter and the substrate, you need to decorate the tank. While you don’t have to add ornaments to a goldfish aquarium, it’s still a good idea to help them feel more at home. Adding a few ornaments, fake plants, and some driftwood will help to make the fish feel at home and keep them stress-free.

Oh, and make sure the plants are fake. Goldfish love to eat plants. They’ll strip your aquarium bare in a single night if you add live plants to it. This was a lesson I learned after buying all kinds of exotic plants for my new aquarium. Let’s just say I didn’t receive the best advice on my first few outings to the pet store

And while most fish require a heater, goldfish are a cold-water fish and are perfectly happy in room temperature water. If the water is too warm, you might actually be shortening your little friend’s lifespan. As long as you don’t keep them in a room that falls below freezing, your goldfish won’t need a heater.  

Change Your Aquarium’s Water Regularly

One of the biggest mistakes I made when I started out was not changing the water. I thought as long as I kept the water topped up, the fish would be fine. But to keep your fish healthy, you need to change the water at least once a week.

But don’t worry, it’s pretty easy to change the water in an aquarium. All you need is a gravel vacuum and a bucket. When you change the water in your aquarium, take out about 10-15% of the water, using the vacuum to suck up all the gunk from the bottom of the tank. Then replace the water you removed with treated tap water. You can buy the conditioner here at Amazon.

See? Pretty easy.

Feed Your Fish Regularly (But Don’t Overfeed Them)

And now the fun part: feeding your fish. Everyone loves feeding their fish, probably because it’s one of the few times you get to interact with your aquatic friend. But unlike most other fish, goldfish are little piggies. They will eat and eat until they’re ready to explode.

And eating that much in an enclosed environment causes a few problems. Mainly lots and lots of poop, and fish waste is terrible for water quality

Even if your fish is at the surface begging for food, you should only feed your fish twice a day, and only as much as they can eat in five minutes. No matter how much they beg, I can promise you they’re not starving.

Also, make sure when you feed your goldfish that you’re using goldfish food. Other foods aren’t specifically made for goldfish and may have too much fat and protein. And too much of either of these can cause all kinds of problems for goldfish (mainly constipation, which leads to swim bladder problems). A great goldfish food to help avoid this Hikari Goldfish Food. And since they float, they’re easy to see how much your goldfish are eating.

Taking Care of Your Goldfish

If you follow all my advice, your goldfish should live a long and healthy life. It’s been six years now since my daughter won Gorby at the local fair, and he’s happily living in a palatial 55-gallon aquarium and now measures a healthy 12 inches! And if I can learn to take care of a goldfish, anyone can.

Good luck with your goldfish!