Goldfish Basics: Get to Know Your Fish

Are you looking to buy your very first goldfish? Are you a beginner or intermediate goldfish enthusiast? If so read on. 

fancy goldfish care

There are a lot of things that you don’t know about goldfish keeping and most people who get their very first goldfish don’t know how to properly take care of their little buddy and end up keeping them in small, unfiltered bowls.

This leads to low life quality and expectancy of your goldfish!

In this article, we will go through some of the basics you need to know to take proper care of your goldfish including the history of goldfish, the types of goldfish you can find, feeding, housing, breeding, etc.

So, let’s jump right in, shall we?

Let’s get started!

Origin Story: The History of the Goldfish

The Goldfish finds its origins in the T’ang Dynasty 618-907 AD and is the first ever domesticated fish.

orange goldfish

The earliest record referring to the domestication of the goldfish date back to the early days of the Sung Dynasty and were mentioned by three different Chinese writers in 960 AD.

There have been several references about goldfish in Chinese literature from 1030 AD which means that they were a popular household pet by that time.

The Original Goldfish Habitat

It is thought that the original goldfish habitat was in the Eastern areas of China from Beijing in the North to Macau in the South. 

Goldfish were thought to have Crucian Carp as their ancestors but, it has now been proven that through the modern scientific methods that they have, in fact, evolved from the Gibel or Prussian Carp.

Selective Breeding

The golden color variation is due to the selective breeding of individual fish which lead to the start of the goldfish that has survived for over 10 centuries and is now considered to be a popular household pet.

Over the ten centuries, goldfish have also been selectively bred for the finnage, body shape, scale type, etc.

Fancy Goldfish: How They Came to Be

There has been no evidence so far that suggests that fancy goldfish have been developed from Common goldfish.

The first ever evidence of fancy goldfish dates back to the year 1200 as a goldfish variety with snow-white body and black spots was mentioned.

In a Chinese publication, an ad was seen in the year 1276 which mentioned snow-white fish as well as gold, silver and other colored fish being sold in Hangchow in China.

tri-colored goldfish

New varieties of the fish are being constantly developed even today while older ones are getting less popular and are even dying out.

Goldfish Types: Goldfish Come in All Shapes and Sizes!

In this section of the article, we will quickly go through the goldfish varieties overview their traits.

Single-tailed Goldfish

  • Common goldfishAs the name suggests, it is the most common type of goldfish and all the varieties are developed from this one. The fish is the direct descendant of prussian carps and is also known as a feeder fish. The most common variant of the fish us shiny-orange in color
  • Comet goldfishThis variety of common in the United States and is similar to the common goldfish but has a long, deeply-forked tail
  • ShubunkinThese are hardy, single-tailed fancy goldfish that have nacreous scales and a pattern
  • London Shubunkins – They have a stout body and short, rounded finnage which is similar to the common goldfish
  • American Shubunkins – They have a slimmer body shape as compared to the London Shubunkin but with deeply forked, pointed tail fins
  • Bristol Shubunkins – These slim-bodied goldfish have well-developed finnage and a large yet moderately forked, tail with a rounded end
  • Nymph goldfish – These are similar to fantail but have single caudal and anal fin. These mutated from fantails or ryukins and other fancy goldfish. All single-tailed mutated fancy goldfish are basically nymph goldfish

Double-tailed Goldfish

These fancy goldfish have double caudal as well as anal fins and are the most popular as well as the most expensive types of goldfish. There are two types of fancy goldfish:

Ones With Streamlined Bodies

  • Wakin goldfish – This fish is similar to the common goldfish but has double caudal as well as anal fins and all fancy goldfish are developed from this one
  • Jikin goldfish – This is similar to the wakin goldfish but has its double caudal and anal fins splay outwards

Ones With Egg-shaped Bodies

The egg-shaped goldfish is the most popular type of goldfish found and have two main types:

Dorsal Finned Varieties

  • Fantail goldfish – This is the western kind ryukin and has an egg-shaped body with double caudal and anal fins, a high dorsal fin, and no shoulder hump
  • Ryukin goldfish – This fish has a short, deep body with a shoulder hump and is similar to the fantail goldfish and has been developed in the Ryukyu islands
  • Pearlscale goldfish – This spherical-bodied goldfish has finnage similar to the fantail goldfish but with a shorter and rounder body. They are susceptible to constipation and have whitish pearl-like raised scales
  • Telescope goldfish – It is similar to the fantail but has protruding eyes and a zoomed vision. The fish should not be kept in an aquarium with rough objects that can harm the fish’s eyes and even cause blindness. 
  • Black Moor goldfish – Is also a telescope goldfish but many tend to treat it as it’s own breed. The black moors have a velvety black or black matte body
  • Oranda goldfish – This fish has a prominent raspberry-like hood which encases its entire head except for its eyes and mouth. They are similar to fantail goldfish
  • Curled-gill goldfish – This fish has curled-gills which are turned outwards and is quite an uncommon variety of fancy goldfish developed by specialist enthusiasts
  • Veiltail goldfish – All the fins as well as the tail are similar to a veil and the fish is prone to fin nipping and are slow-moving because of the fins 
  • Tosakin goldfish – The goldfish has undivided double tail fins which curl their tail at the ends. This breed is a distinctive one that has a large tail fin that spreads out horizontally

Dorsal Finless Varieties

  • Eggfish goldfish – This variety is similar to the wakin but has no dorsal fin
  • Pompom goldfish -This fish is similar to the eggfish but it has larger nasal septa which are called “pompoms” and is developed from the eggfish goldfish
  • Lionhead goldfish – This fish similar to the eggfish goldfish but has a head growth which is a soft, spongy one and is developed from the eggfish goldfish
  • Ranchu goldfish – This one is compared to lionheads, but have a more downturned tail as well as tail fin. These have more-arched backs and shorter tails that which are tucked-in
  • Celestial eye goldfish – This fish has double tails and a pair of upturned, telescope eyes with pupils gazing skyward and is developed from the dorsal-less telescope eye goldfish.
  • Bubble eye goldfish – This small bubble eye has its eyes accompanied by two large fluid-filled sacs which are fragile and can get ruptured easily

Goldfish Diseases: Things You Need to Know

goldfish disease

In this section of the article, we will quickly overview some of the more common goldfish diseases.

Let’s start.

White Spot Disease (Ich)

This is extremely common in aquariums, and usually affects new goldfish which are stressed out after a long car ride to your home.

  • Causes of Ich – This is caused due to ich parasites in the water which attack stressed out goldfish that have a lowered immune systems so, anything that causes stress can make your goldfish susceptible to common goldfish diseases
  • Ich Symptoms – The goldfish are covered with something the resembles small grain and the fish breathe heavily and scratch themselves against tank objects

Swim Bladder Disease

Fancy goldfish can have buoyancy problems which are a result of other common goldfish diseases. 

  • Causes of Floating Problems – The goldfish might experience floating problems if they are fed poor quality food, overfed, or not fed enough fiber. Constipated goldfish may also experience difficulty swimming
  • Floating Symptoms – The fish swim erratically, sideways, and even swimming upside down. The fish may also look physically swollen 

Fin Rot

This happens to goldfish under a lot of stress and is a bacterial infection named tail rot

  • Causes of Fin Rot – Stress makes the goldfish susceptible to some types of bacteria. Common goldfish diseases, overcrowding, poor water quality, sudden temperature changes, etc. can all cause the immune system to lower and the condition to develop​​​​
  • Fin Rot Symptoms – The fish has ragged, torn, or red-streaked fins.The edges of torn fins become white as bacteria eat away the fins on your goldfish

 Fungal Infection

Goldfish develop fungal infections if the water quality is poor and these diseases can affect goldfish that are sick from other common goldfish diseases.

  • Causes of Fungus – Stress and a lowered immune system prompts fungus to grow
  • Fungal Disease Symptoms – Cotton-like growths along the fish’s body and fins are signs of a fungal infection

Gold Dust Disease

This is similar to white spot disease and looks like small grains of dust which start on the backs of goldfish.

  • Causes of Velvet – The gold dust disease is found in tanks where new fish are present and is caused due to stress
  • Velvet Symptoms – The goldfish have a whitish-yellow film on their skin and golden specks of dust. This will starts on the backs of goldfish before spreading to the body and gills

Anchor Worm

The anchor worm is not actually caused by a worm and is one of the most common goldfish diseases in freshwater ponds.

  • Causes of Anchor Worm – The worm can develop in tanks with recently purchased goldfish. It is important to quarantine new fish or plants else you may have an outbreak of anchor worm after a week 
  • Anchor Worm Symptoms –You may notice whitish green hair-like creatures which hang from the bodies of the goldfish and the areas attached are usually red and inflamed

Fish Lice (Argulus)

Fish lice is caused due to parasite crustaceans and are common in goldfish ponds.

  • Causes of Fish Lice – Fish lice hop a ride on new goldfish that haven’t been treated in a quarantine tank
  • Fish Lice Symptoms – The lice have round greenish-brown, disk-shaped bodies and are seen moving around the throat, stomach, and bases of fins

Hole in The Head (Hexamitiasis)

This parasitic disease can affect freshwater as well as saltwater fish and, in some cases, lesions appear on the fish’s face.

  • Causes of Hexamitiasis – ​The causes have been long debated however, activated carbon has been linked to it
  • Fish Lice Hexamitiasis Symptoms – ​Lesions on the fish’s body which look like holes

Black Smudge

Black smudge or black spots on the fish are signs of this disease. They start to develop around the fish’s fins, tail, and scales.

  • Causes of Black Smudge – Parasites in the water are linked to this disease
  • Black Smudge Symptoms – Black smudge or black spots on the fish are signs of this disease


This diseases is caused by the buildup of fluid inside the body cavity or tissues. This can also indicate underlying issues.

  • Causes of Black Smudge – ​There are several causes of this condition such as temperature, bad quality of water, stress, etc.
  • Dropsy Symptom – The defining symptom of this disease is bloating

Other know issues goldfish can face include:

  • Clowdy Eye
  • Costia
  • Cotton Wool
  • Flukes
  • Trichodina
  • Ulcers
  • Velvet

The Basics of Goldfish Breeding

Breeding goldfish isn’t an easy task as the fish are hard to breed when in captivity.

For the breeding to be successful, there are a lot of different factors that need to be tended to such as providing the fish with plenty of water, setting a specific temperature, providing the fish with plenty of space, etc.

You also need to invest in some equipment to start breeding your goldfish.

You’ll have to get a fry tank, heater, live plants, sponge filter, etc. along with a female and a male goldfish to mate. The fish can usually be sexed from around 1 year of age.

You should keep more males than females as it increases the chance of successful spawning. But, keep in mind that you should only keep as many fish in the tank as you have room for. Overcrowding won’t lead to successful mating.

Breeding Temperature 

Goldfish normally breed in the spring when living in the wild. So, the breeding is triggered by the change in temperature.

wooden thermometer

To ensure successful breeding, you should first lower the temperature of the tank to 50°F to 54°F and then, to induce breeding, raise the temperature 3°F per day until it’s between 68°F to 74°F.

Spawning Behavior 

When the Goldfish are ready to breed, the males have white pimple-like growths on their gills and the females seem to look fatter than usual.

The male will chase the female around the tank and will poke her in the abdomen.

This is called spawning behavior.

Following this spawning behavior, the female will probably swim to a planted area in the tank and lay her eggs which are really sticky and are easy to spot on the plants.

side view goldfish

When the male notices the eggs, he swims over to them and sprays his sperm over them to fertilize them.

What to do with the Goldfish Eggs?

It is important to note that goldfish are known to eat their own eggs so, they can’t be left in the tank and should be removed from it as soon as possible.

You should remove the whole plant using a spawning mop and and put them in a small fry tank and ensure that the temperature of that tank is between 68°F to 74°F. You should use a heater raise the temperature of water when necessary.

Lighter colored eggs have a higher chance of hatching, so you can dispose of dark eggs and only keep the lighter ones.

Just wait for them to hatch!

​Goldfish Diet 101 

goldfish diet

If you feed your goldfish a varied diet, it will maximise its health.

You should give your fish a mixture of specialised goldfish granules and flakes as a staple diet.

These should ideally be supplemented with live brine shrimp and a mixture of daphnia, veggies, and frozen brine shrimp.

You can also supplement your fish’s diet with small invertebrates, duckweed, and scalded peas.

Keep in mind that an ideal goldfish diet must be high on carbohydrate level and you should soak freeze-dried food before giving it to your fish avoid digestive upset.

It is important that you feed your fish 2-3 times daily and avoid overfeeding as it can cause indigestion.

swim bladder disease

You should only feed your fish the amount of food it can have in under two minutes.

These fish feed at all levels and accept most foods. However, small floating pellets are ideal as they help keep the tank clean and excess can be removed easily.

Purchasing Goldfish from the Pet Store

The first thing you should look for when you enter the pet store is to observe whether or not the staff keeps the place clean. If the place seems unorganized and dirty, you are better off turning right back and heading towards the door.

If you do find the place to be clean and tidy, you should head straight towards the fish and take a look at the following.

goldfish behavior

In this section of the article, we will go through how you can purchase healthy goldfish for yourself. Let’s begin.

Are there chemical smells around the aquarium? If this is the case, you should look for cover-less aquariums.

The smell usually means that insecticides have been sprayed which is dangerous for goldfish in the vicinity.

So it is best that you avoid purchasing your goldfish that are swimming around in tanks contaminated by such chemicals.

The number of goldfish deals you see Pet stores are known to overstock to sell more fish and the staff can’t really pay attention to everything at the same time, there are going to be some dead goldfish in the store.

However, if you see more than a few dead fish in the same aquarium you need to keep away from them as they could be sick and carrying diseases.

Is the store trying to selling unhealthy fish? You should take a look at the tints in the water as they are signs that the goldfish are being treated for some disease. It isn’t right for shop owners to dell you infected fish. 

If you do wish to purchase your fish from a treated tank, be sure to ask long the aquarium has been medicated and be back when the treatment is over.

In case the goldfish are being sold in poor condition, you should take your business elsewhere.

How knowledgeable are the staff? Some people from the pet store’s staff are completely clueless and that’s fine. The thing is that the person you speak to may not be working in that particular area in the store.


However, it is extremely important that whoever is handling your fish knows what he/she is doing and is open to your questions and queries.

If not, you shouldn’t buy from that store. 

Is there loud music playing in the background? The thing about Goldfish is that they get stressed out if there are loud noises nearby.

And, as I have mentioned in the previous section, stressed fish are simply more vulnerable to goldfish diseases.

How do the actual goldfish look? Are they healthy? Look for red veins on fins are as they are signs of stress and so are blemishes on the scales or body.

Torn fins may also mean stress, a bacterial infection, or quarrels with other fish.

If you feel that something doesn’t look right, you should buy your goldfish from another store. The goldfish aren’t probably being cared for properly or were bought from bad stock.

If you’re unsure of a certain goldfish variety, you should always ask questions!

Make sure that you also find out what the fish are fed and also how often the tank gets cleaned before you get yourself a goldfish from the store. 

You should also take some time to observe the fish and look for erratic behaviors.

If everything looks good, be confident that you bought healthy goldfish and you can now start quarantining your new pet!

Housing a Goldfish 

Did you know that goldfish cannot survive in unfiltered bowls?

big eye gray goldfish

While the mass media would have you believe otherwise, goldfish need a tank with a filtration system installed to live their entire lifespan and be healthy. And, that just isn’t possible in a small, unfiltered bowl.

Theoretically, a goldfish may be able to survive in a bowl if the water is changed every day.

That just doesn’t seem practical, right?

Goldfish Size and Tank Size

What most people don’t understand is that goldfish can get quite large in size—they aren’t always as small as advertised!

biggest goldfish

In fact, some fancy goldfish varieties—especially the kind that have a split or double tail can get up to 6 to 8 inches in length!

Yes, I’m talking about inches.

Other single tail varieties of Goldfish like the comet, common, wakin, and shubunkin can even get to double the size of the fancier varieties so, they do much better when kept in a tank size which is over 100 gallons, and they do even better than that in a pond.

Never Ever Ever Keep Goldfish In A Bowl

The Golden Goldfish Keeping Rule

When it comes to fancy goldfish, the rule of thumb is 20 gallons for the first fish, then 10 gallons for each additional fish.

Keep in mind that single-tailed fish far more room, and at least 40 gallons per fish. For these varieties, a pond is the best option.

While this rule does seem quite excessive for someone new to goldfish keeping but, it is important.

A small tank that has a large amount of goldfish is basically a recipe for disaster.

how many goldfish can i fit

First of all, it would be hard to keep the levels of ammonia under control which won’t be affected at all by any number of water changes. 

Secondly, due to the waste load being placed on the filter, the fish will get sick and eventually start dying off.

So, you should only keep as much fish as your tank can handle for them to live a happy and healthy life.

Acrylic or Glass Tanks: Which Are Better? 

The good thing about acrylic aquariums is that they are light in weight, durable, retain more heat, have spotless sides, have a clear and more realistic view, and are available in a variety of shapes and sizes.

bubble eye goldfish 2

However, glass aquariums hold their shape when unsupported, are heavy, have seams on the corners, and the design options are limited.

Keep in mind that each material has its pros and cons and you should choose the one that suits your requirements.

Goldfish Tank Filtration Systems

Fluval C3 Power Filter

Goldfish actually do need a filter.

These fish are quite messy and produce a lot of waste so, unless you change their water on a regular basis, the aquarium can get really messy and will get polluted and poisonous to the fish. 

These fish are quite messy and produce a lot of waste so, unless you change their water on a regular basis, the aquarium can get really messy and will get polluted and poisonous to the fish. There are two basic types of filters:

  • External filters: These sit outside the goldfish tank and contain more filtration media, which means that they do a better job at cleaning the water. These can also be hidden using aquarium cabinets 
  • Internal filters: These are usually submerged in the goldfish tank and are quite effective 

Both the external as well as internal filters are available in various sizes and offer different flow rates, or water filtered per hour.

Common Filtration Systems

 In this section of the article, we will quickly overview some of the most common filtration systems for goldfish.

1. Hang On Back or HOB Filters

Penn Plax Cascade Hang-on Aquarium Filter With Quad Filtration System Cleans Up To 50 Gallon Tank

The hang on back filters, also known as the HOB filters are one of the most common filters you’ll find in almost any pet store.

These filters feature a small pump which pushes water into a compartment which is stuffed with filtration media and the, back in the water. This is also known as an all-in-one filter.



These are usually quite inexpensive and are easy to set up. They can also be hidden behind a tank background.

You have to incur the recurring expense of buying new cartridges. In some cases, water current can be an issue and there limited room for beneficial bacteria to grow so the it us not as effective for goldfish and also has danger of mulm buildup.

2. Sponge Filters

Huijukon Air Pump Double Sponge Filter for Aquarium Fish Tank Up to 55 Gallons (Fiter)

There are superior to hang on back filters when it comes to filtering water for goldfish.

These sponge filters work by pulling the water through a sponge with the help of an air pump which is attached to the airline tubing and the little sponge holes make an ideal environment for beneficial bacteria.


There is no risk at all for mulm buildup and they have a gentle current. The aeration bubbles also help with oxygen and the filter is simple to use and can easily be hidden behind rocks or plants.


The debris buildup on the sponge may restrict the growth of the beneficial bacteria and there no provision for manual particle removal. These also require frequent cleaning.

3. Canister Filters

EHEIM Classic 250 External Canister Filter

The canister filters are a much more powerful solution than either of the two options that I’ve mentioned above.

These filters work by running from the aquarium water to the filter and then back into the aquarium.


These filters are big enough to put various materials inside and afford the ability to adequately filter the water so as to reduce the need for frequent water changes.


This can be an expensive solution and may be difficult to clean. This is more complicated to configure and has poor gas exchange without the use of a spray bar. This could also have too much current.

4. Undergravel Filters

Lee's 40/55 Premium Undergravel Filter, 12-Inch by 48-Inch

As the name implies, undergravel filters are positioned under the layer of gravel in the tank and could work very well—in theory, that is.

These work by placing a grid underneath the gravel at the bottom of the tank and pulling the debris through the gravel bed.


The best part is that lots of surface area can be colonized by the beneficial bacteria and the solution is better than gravel alone.


This gets dirty quite often and can be difficult to clean. You also must have gravel in order to work which is something that isn’t recommended for goldfish.

5. Wet/Dry Filters

Eshopps AEO13025 Wood 200 No Overflow Filter for Aquarium

The Wet/dry filters ot the trickle filters are the best filtration systems that you can install in your goldfish tank.

These work by pumping the water from the tank into a tray which is situated above it where it trickles over the different layers of filtration media.

Just like in the canister filters, what is inside these filters is totally up to the aquarium owner. So, you can customize them according to your needs.


There is lots of room for the beneficial bacteria to grow and there are no current issues at all. The best thing is that this is a very oxygen-rich end product and can reduce the need for water changes and altogether eliminates nitrates.


The DIY versions are an eyesore and these require some creativity to disguise.

Final Words: Goldfish Basics: Get to Know Your Fish

The Goldfish finds its origins in the T’ang Dynasty 618-907 AD and is the first ever domesticated fish.

school of goldfish

Goldfish were thought to have Crucian Carp as their ancestors but, it has now been proven that through the modern scientific methods that they have, in fact, evolved from the Gibel or Prussian Carp.

The earliest record referring to the domestication of the goldfish date back to the early days of the Sung Dynasty and were mentioned by three different Chinese writers in 960 AD.

There have been several references about goldfish in Chinese literature from 1030 AD which means that they were a popular household pet by that time. 

Goldfish actually cannot live in a bowl and need a tank with a filtration system to live their lives happily. 

comet goldfish

They need their elbow room, too!

In this article, we went through everything you need to know about goldfish and all the basics. For a more detailed explanation on different topics, be sure to dive deeper into the website.

More in depth article you may enjoy:

Some Mistakes Made By Goldfish Keepers 


Air Pump


Tank Temperature

Water Filtration

Goldfish Tank Water Cycling