How to take care of a goldfish

When people think about keeping fish at home, the goldfish is definitely top of mind for most. That being said, proper goldfish care is not widely understood.

Now, I like to entice readers with interesting statistics. So, I tried to find out how many goldfish are kept as pets around the world. The best I can do is to tell you that more than 48 million Americans ate at least one bag of Pepperidge Farms Goldfish crackers in the past month.

While this doesn’t help us calculate the world goldfish population, it does speak to the popularity of them and the solid place they have in our collective consciousness. So the lack of knowledge around caring for goldfish properly is a cause for concern.

Ultimate guide to goldfish care written around two swimming goldfish on white bgThis article will take care of that.

In this one page care sheet, this complete step-by-step guide on how to care for goldfish, we’re going to give you everything you need to meet all of their needs.

Along the way, we’ll dispel a few myths, let you know what equipment you need, detail how to set up a goldfish tank (yes, tank – never a bowl!), how many goldfish you can keep at once, tips on buying healthy specimen, as well as daily, weekly and monthly maintenance tasks and more!

Keep reading and get ready to enter the wonderful world of caring for goldfish.

Buying and Adding Your Goldfish to the Tank

The best part is here! Time to go out and choose your goldfish and bring them home. To help you make the best choice, here are some factors to consider and signs to look for.

Should I Buy Male or Female Goldfish?

Unlike with some species, like bettas, it isn’t strictly necessary to separate your goldfish by gender.

The males are unlikely to be a threat to females or each other. In terms of attractiveness, male goldfish are sometimes a bit showier than females; their bodies might be slightly smaller, but the fins are often larger.

It can be extremely difficult to tell males and females apart, even for experienced aquarists. The easiest way to determine gender is to wait for breeding season. This happens naturally during the spring, but the conditions can be artificially created in a tank to force breeding.

Males will start to show breeding tubercles along their gill covers and by the pectoral fins. The tubercles look like small white dots and are quite distinct.

Outside of breeding, or spawning season, you may be able to recognize a male goldfish by a large ridge running from the back of the pelvic fins to the vent. The vent is the opening through which males release sperm and females release eggs.

Ultimately, it doesn’t really matter whether your goldfish are male or female unless you plan to breed them. Ask at your aquarium store for help selecting the gender of your choice. Even if you do get a mix, however, it may not lead to unwanted babies. They won’t breed unless the conditions are just right.

How Many Goldfish Can I Keep?

Goldfish are social fish and will thrive in the company of others of their own kind. How many you can keep at once is only limited by the size of your aquarium. Remember the rules we gave earlier?

Make sure not to keep a mix of single tail varieties and fancy goldfish in the same tank. The single tails are more aggressive, perhaps from being genetically closer to their wild relatives, and will out-compete the fancies for food.

Making Sure You Pick Healthy Fish

Buying a fish and bringing it home, only to have it die within a short time is very frustrating. This is especially true when you know you did everything right with your tank. Often what happens is the fish came home sick. Starting with a healthy goldfish can save you from disappointment.

For your best odds at choosing a healthy fish go to a breeder or an aquarium store rather than a pet store. From there, it’s all about observing the fish for certain tell-tale signs of sickness.

First, look at the conditions of the tank. Is it dirty? Overcrowded? Are there dead fish that haven’t been removed? These are all indicators that the environment isn’t healthy, and therefore the fish may not be either.

Physical signs of an ailing goldfish include torn fins, swollen eyes, white spots, clamped fins, and lethargy. You want to choose ones that are bright and shiny, and swimming around upright at a comfortable pace.

Adding Your Goldfish to the Tank

how to introduce new fish to your aquarium written beside a young boy doing just thatAt long last, we’ve reached the moment you’ve been working towards! The tank is ready, and your healthy fish are home. Time to move them in!

Hold up there, cowboy – you can’t just open the gate (or bag, in this case) and set them loose. You run the risk of shocking your new fish and adding any contaminants that hitched a ride from the aquarium store. I’m pretty sure this is how I once ended up with snails without buying any.

Here’s a summary of the steps to follow when you’re adding new goldfish to a tank:

  • Switch off the aquarium lights (the fish will be too close)
  • Float the sealed bag in the aquarium for 10-15 minutes
  • Open the bag and roll down from the top several times
  • Scoop or otherwise drain 1/4 of the water from the bag
  • Using a clean cup, add a small amount of aquarium water to the bag
  • Continue adding water every 5-10 minutes for 1 hour
  • Carefully capture your goldfish with a net and gently place it in the tank

Moving your goldfish to their new home correctly is a crucial step. To learn more about how it should be done, we highly recommend reading our complete guide to introducing new fish to an aquarium.

Food and Feeding

Feeding goldfish is more complicated than simply dumping in some flakes and hoping for the best. It’s important to know what an appropriate diet is and to understand how they eat.

Are they herbivores or carnivores? Bottom feeders or surface feeders? Read on for the answers!

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What do They Eat?

How to feed your goldfish written beside a cartoon fish carrying a plate of chipsOne of the reasons goldfish are such hardy survivors is they’ll eat just about anything. Like us, they are omnivorous creatures, meaning they’ll eat both meat and vegetables to have a balanced diet. And, like some of us, they are voracious eaters, too!

The easiest way to ensure they get the proper nutrients is to feed them specially formulated flakes for goldfish. Once the flakes hit the surface, they’ll come rushing up to get them. Flakes that sink will also be found and gobbled up if they’re still hungry.

You can also try pellets for goldfish. Since they sink, they’re perfect, because they enjoy rooting around the bottom looking for food.

As far as treats go, they will happily munch on anything from brine shrimp to bloodworms. You can also give them leafy green vegetables like kale, chard, and spinach, as well as broccoli, corn, shelled peas, and cucumber.

For fruit, you can offer watermelon, orange, and peeled grapes. Make sure to remove uneaten portions after a couple of hours to avoid fouling your tank. Treats should be restricted to just 1 or 2 times a week.

Since they’re indiscriminate eaters, take advantage of that to enhance both the health of your goldfish and their lifestyle. Vary their diet rather than sticking to a single food source. Not only will this provide a variety of nutrients, but it will also make life more interesting for your goldfish.

How Often Should You Feed Goldfish?

In the wild, goldfish eat a lot, but they burn it all off since they’re so active. Your average aquarium dweller though is somewhat more sedentary, so he or she requires fewer calories.

Feed your goldfish 2 or 3 times a day, but only small quantities. A good rule of thumb is to offer as much food as can be eaten in about two minutes. More than that and you risk either overfeeding your fish or polluting the tank with rotting food.

If you’re not home during the day, you might want to invest in an automatic fish feeder to be sure your tank buddies are fed on a schedule and are given the right amount.

Maintenance – Daily, Weekly and Monthly Tasks in the Care of a Goldfish

Nothing worth having comes without a bit of work! Here are the tasks you can expect to perform on a regular basis to keep your goldfish healthy and happy.

Daily Tasks

  • Feed your goldfish (2-3 times)
    • Make sure everything is being eaten to avoid waste build-up
  • Inspect heaters, lights, pumps, and filters for functionality
  • Monitor the water temperature to be sure it’s between 65-74F (18-23C)
  • Look for signs of stress or disease
    • Abnormal behavior like erratic swimming or scratching themselves on rocks and decorations
    • Check fins for damage
    • Look for white spots or fungal growths

Weekly Tasks

  • Test water for pH, bacteria, nitrites, etc.
  • Use a vacuum to remove waste from substrate (this may vary – it might need cleaning more or less often)
  • Replace 20% – 40% of the water

Monthly Tasks

  • Clean your filters and replace the media
  • Trim any live plants getting too big
  • Remove and clean all decorations, artificial plants, rocks, etc.
  • Scrape or wipe excess algae from walls
  • Wipe clean lighting covers (algae and hard water scale build up over time)
  • Review food, medicine, test kits, etc. for expiration dates and throw out anything expired

Goldfish Tank Mates and Compatibility With Other Fish

Goldfish are generally sociable fish that get along, or will at least not bother many other types of fish. However, as we said before, do not mix single tails with fancies.

Aggressive species of fish should be avoided, like bettas and cichlids. This is especially true if you’re keeping fancy varieties; those big, beautiful tails are easy targets for fish that like to nip.

Here are a few species of aquarium fish that make ideal tankmates for goldfish. It’s by no means a complete list, but it’s a good place from which to start.

  • Rosy Barb
  • White Cloud Mountain Minnow
  • Weather Loach (or Dojo Loach)
  • Zebra Danio
  • Plecos
  • Apple Snail
  • Ghost Shrimp/Red Cherry Shrimp
  • African Dwarf Frog

Remember, there’s more to it than just social compatibility. Goldfish prefer cooler water than many tropical fish. So, while a breed of fish might be marked at the aquarium store as “community” fish, they also have to tolerate the same water conditions.

Goldfish Care Tip #4: Buy Quality Goldfish Food

To feed your goldfish on a regular basis, you need goldfish food.

Don’t just buy the first brand you see either. To meet all of the nutritional and dietary needs of your goldfish, you’ll need to know what to look for.

Not all commercial brands are created equal. If your goldfish are malnourished, an overwhelming disease outbreak might be around the corner. Goldfish need particular nutrients to thrive. Young goldfish and many fancy varieties especially need protein-rich foods to develop and grow.

Goldfish are also ravenous scavengers. Many times, they’ll swim right up to the aquarium glass and nuzzle their noses, begging for an additional meal. But don’t let their begging antics fool you!

Goldfish have sensitive digestive systems. If fed too much too soon, there might be even bigger problems than a hungry goldfish.

Learn all about…

  • Goldfish nutrition
  • Recommended brands
  • Foods unique for certain goldfish types
  • How often to feed your goldfish and when
  • And the importance of food variety

There are many different kinds of food available, but the key is finding the right brand for the dietary needs of your goldfish.

Goldfish Care Tip #6: Explore Goldfish Breeding

Goldfish breeding is a fun and worthwhile experience if you’ve been raising goldfish for a while. You can even make a side income just breeding and selling goldfish fry (once they’ve matured of course). Goldfish breeding is also an incredible learning experience, and hatching your first batch of fry can be exhilarating.

Learn the fundamentals of…

  • Goldfish breeding basics
  • How to prepare your goldfish for mating
  • How to hatch your first batch of fry
  • What to do when those babies hatch
  • And how to raise young goldfish

If you want to explore goldfish with different traits or even show off your goldfish at local shows, breeding is an excellent first step.

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Goldfish Care Tip #7: Build a Goldfish Pond

Goldfish, like koi, are wonderful pond fish because of their large sizes and hardiness. Some goldfish varieties were even developed to be looked upon from above (celestial eye goldfish, for example).

But while most goldfish with streamlined bodies are fine kept in ponds, other fancy varieties do best indoors because of their sensitive, exaggerated features.

Get detailed advice on…

  • Which goldfish types are best kept outdoors
  • If a goldfish pond is right for you
  • How to develop a pond environment
  • How to care for goldfish in a pond
  • What to feed your pond inhabitants
  • And what to do over the winter before the pond freezes over

Keeping goldfish is a wonderful experience. But it’s up to you to take the actions necessary for long-lasting, healthy fish.

Since goldfish can’t care for themselves, they depend on you for their goldfish care. It’s up to you to maintain a healthy goldfish tank, feed your fish quality goldfish food, prevent (or treat) goldfish diseases, and even take your goldfish hobby to the next level by setting up an outdoor pond or hatching your first batch of fry.

Remember: You control the lives, happiness, and well-being of your goldfish. If you give these amazing creatures the goldfish care they deserve, they will thank you for years and years to come.

Choose The Best Goldfish Tank Filter

Choose The Best Goldfish Tank FilterWhen I first got my first pet goldfish I was over the moon but having a water filter never crossed my mind. I just filled it up, decorated and then added the fish.

They must have been raging!

If you are unsure if your goldies need a filter check this article out.

As I have learned more about keeping fish I know I screwed up.

If I had added a filter this would have increased their chances of survival but I really should have let the water cycle first (more on that later).

Fish are living creatures the pee and poop just like all of us. This has to go somewhere!

Would you like to swim in your own excrement?

Didn’t think so.

A tank filter like the EHEIM Classic 250 will remove excess food, decaying organic matter, free-floating particulate, dangerous chemicals, and the fish’s waste products from the water.

When you choose a goldfish tank filter you are faced with a choice an internal filter or an external. It’s pretty self-explanatory, one sits in the tank and the other outside.

I prefer the external because they contain more filtration media and therefore do a better job of cleaning your water. You can also tuck the filter out of the way in a cabinet to make your tank look better and less cluttered.

Now if your tank is 20 gallons you want a filter that is able to filter 10 times the amount per hour.

So you would want a 200 gallons per hour filter for this tank.

What Is The Best Goldfish Tank Temperature? 

Caring For GoldfishGoldfish are pretty hardy creatures but you should still strive to create the perfect environment for them.

So what is the best goldfish tank temperature to keep our goldies happy?

The ideal tank temperature for goldfish is around 60-75 degrees Fahrenheit.

The problem with goldfish is they hate inconsistency. So if your tank is continuously changing temperature you will end up with unhappy fish.

Choosing a large tank is better to keep the water temperature consistent enough for goldfish. If you do notice your temperature is fluctuating, you might consider a heater with a thermostat and set it to the correct temperature.

In most cases, you will not need one though.

What Is The Best Fish Tank Substrate For Your Goldfish?

The tank substrate is basically the tank floor and it is the first aqua-scaping decision you will have to make.

Choosing the best fish tank substrate will help keep your goldfish happy and safe in their environment.

With goldies they are pretty happy with most to be fair but here are my takes on each.


Aquarium GravelGravel is probably the most common substrate for most new fish owners. It comes in a variety of colors and makes it look funky and cool.

Now it won’t affect your fish directly but food and excrement can get stuck in the gravel. This means you will have to be more vigilant with your tank cleaning schedule.

On the other side of the coin, gravel will hold on to good bacteria too.

But unfortunately, the bad bacteria is too harmful!

Goldfish are big waste producers and if this is trapped in the gravel at the bottom, the tank will become a pool of bad toxins.

Over time this will take its toll on your little buddies immune system.


Aquarium SandSand, in my opinion, is a much better choice for your goldfish tank. Some people have actually said that a fish ingesting a little bit of sand is good for there digestion.

Healthy fish equals happy fish!

Sand went out of fashion as people claimed it irritated the little dude’s gills but this was later disproved.

Wild goldfish swim in muddy, sandy rivers so why shouldn’t our domesticated fish?

The only problem is the appearance it’s not as pretty as blue, white and green gravel. In my opinion, though, it looks more natural.

And your goldfish will love to dig around in it also.

For waste, sand is great as it will actually just sit on the top. Not as great to look at but with a little vacuum your tank will be much better for your fish.

This all means a lot fewer toxins.

No Substrate

When you attempt to breed goldfish it is recommended not to put a substrate down. This keeps the water quality perfect for the arrival of the babies.

It also keeps your fish free from substrate related injuries, such as ingestion.

The only problem with a bare bottom tank is aesthetics. It’ doesn’t look as great. Having said this, goldies thrive a lot more in a substrate-less aquarium.

Place some rocks with live plants attached or set the rocks on goldfish approved plastic plants.

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Wood is another option just make sure that you let it get used to the water or you could end up with a tan colored aquarium.

Decorating Your New Tank

When it comes to decoration or aqua-scaping you have full control. The only thing you need to be sure of is… is it safe for your goldfish tank?

Caring For Goldfish

Most aquarium dealers in your area will only stock safe decor. If you are buying online make sure you buy from a reputable retailer. Look at reviews and see what others think before you dive in and buy your tank ornaments.

I prefer to keep things looking natural so I tend to go for plants, rocks, and wood. I also live by the less is more saying. You do not need every area of the aquarium to be covered with decor.

Clutter reduces the amount of room your fish has to swim in. Do I need to remind you how important space is for goldfish?

For me, I would settle for a bit of wood that has loads of areas for fish to swim through and hide.

I would maybe add some rocks too.

Going minimal and natural is a lot more fresh and clean looking. I totally love the natural look but if you see a goldfish safe Nemo or Dory then go for it!

Do You Need Plants For A Goldfish Tank?

When you are choosing plants for your goldfish tank you must check that they are safe for goldfish.

Goldies love munching on plants, it adds variety and adds variation to your goldies diet.

For this reason, you should buy fast growing plants. Slower growing plants might not get the chance to grow.

Goldies love having a little nibble… ok, a big nibble!

You just need to remember goldies love to dig around in the gravel and this could lead to the plants being pulled out and left floating at the top. Not a big problem though, just attach to your rocks or wood.

Weighing them down will keep the plants in place.

So what plants work well for your goldfish aquarium?

Anacharis Plant

Anacharis PlantThis is a hardy beast and perfect for your first goldfish tank. It is very fast growing so no chance of your goldfish eating before it grows.

In cold water tanks, it doesn’t need a fertilizer or substrate supplement, so it is extremely low maintenance. You may have to cut back or prune though.

It works well being buried in the substrate or free flowing.

Lastly, anacharis is a great plant for boosting oxygen levels within your tank and absorbing excess nutrients and minerals.

Java Fern

Java FernJava fern is another easy plant for your goldfish tank and looks great too. This one is a hardy plant but has a bitter taste, so your goldfish will not be as fond of this one.

However I am sure they will give it a go.

This is a great plant for no substrate setup as it will not root!

Weigh it down with a rock or driftwood and it will thrive. If you do notice it wilting it could be due to the sunlight.

Bright conditions are not great for Java Fern, moderate light is best.

Now that you have a couple of plants and decorations it is time to get the water ready for your goldfish tank.

What kind of aquarium do Ranchu Fancy Goldfish need?

Goldfish can grow to be quite long, and even the smaller types of goldfish require a decent size tank for swimming space as well as to prevent oxygen shortages.

A 10-gallon aquarium is never recommended unless you are only planning on bringing home a single fish and the fish will be a small one, for example feeder goldfish.

Goldfish are social creatures and only bringing home a single fish for a 10-gallon tank may cause your goldfish stress and boredom.

A 20-gallon tank is a good size to start at while your goldfish is still young.

However, you should be prepared to purchase larger aquariums down the road.

If you plan to have more than one goldfish in a tank, then you should plan at least 10-gallons per goldfish.

This rule of thumb will help prevent overpopulating an aquarium as well as prevent oxygen shortages.

Also, smaller tanks usually require more frequent water changes and tank cleanings.

Goldfish are messy and cannot live in a small space with their own waste for too long. Can you blame them?

Other tips that can come in handy when deciding on a goldfish aquarium:

  • You may want to add a couple of freshwater snails to you goldfish aquarium. They are natural algae eaters and can help keep the tank clean between weekly cleanings.
  • You should also choose an aquarium with a large surface area (such as a rectangular tank). The more surface area a tank has, the more room your goldfish have to swim and oxygen shortages should happen much less.

Get to know your Ranchu’s temperament and personality:

Ranchu Fancy Goldfish are social creatures especially when they share their tank with similarly “handicapped” fish. Therefore, they would be lonely in a tank alone.

 Their tankmates should be the Lionhead, the Bubble Eyed Fancy Goldfish, or the Celestial Eyed Fancy Goldfish. Ranchus (and other goldfish) recognize their tankmates and their owners, alike. So, give them something to recognize!

ranchu fancy goldfish

The Ranchu can provide your home with a natural stress reliever, simply by just existing. It is your job to make sure your Ranchu Goldfish is never stressed or under any kind of duress. However, they are at risk for the following common goldfish diseases.

  • Goldfish ICH: Also known as White Spot Disease, is a pesky parasite that latches onto the Ranchu’s body and feeds until it has grown enough to reproduce and start the cycle all over again.
  • Other parasites: Argulus (fish lice) and Anchor Worms
  • Bacterial infections: Tail or Fin Rot (disintegrating fins caused by a number of health issues), Dropsy (a kidney disease), and fatal Tuberculosis.
  • Fungal Infections: Black ICH
  • Swim Bladder Disease: Condition where the goldfish has difficulty finding their swimming balance and may swim in off patterns.
  • Cloudy eye: Can be caused by any number of health conditions.

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