Goldfish – Habitat, Care, Feeding, Tank Size, Breeding

Out of all the pet fishes across the globe, goldfish are definitely among the most loved ones. This is seen through the increasing number of people who want to keep them.

Of course, you cannot blame such people because goldfish are just spectacular creatures.

Even with being said, there are also people who want to keep goldfish but do not know anything about them. Well, here is a complete guide on everything to do with goldfish.


The first thing you would notice when looking at goldfish is their bright colors. Most of the time, you will find goldfish with yellow-orange bodies. There are also other goldfish types that have dull-colored bodies. You may find them with brown bodies, others with grey and even black.

In as much as the exhibit such great colors, in case of certain factors, they can lose them. One of these circumstances is the lack of exposure to sunlight.

Goldfish have pigment in their skin that is reactive to light. This then means that when their skins lack enough exposure to light, it has a negative effect on their skin. With time, their skin could lose its color and turn to white.

Just like goldfishes’ body colors vary, so do their sizes. The average size of goldfish is 4 inches.

However, you may find other goldfish growing to even 4 or 5 times that size. For instance, in 2008, according to the BBC, the largest goldfish measured about 19 inches.


Goldfish is a freshwater fish believed to have originated from China. Over time, they spread all over the world and now live in ornamental pools and aquariums. You will also find some in the wild.

For such a kind of goldfish, most of the time, you will get them in slow-moving water bodies. Some examples are lakes, ponds, rivers, and streams. You will also find them in areas where the water is a bit murky.


The food goldfish eat in the wild is slightly different from what they eat when in an aquarium/at home.

Diet in the Wild

Goldfish in the wild feed on crustaceans and insects. They are also known to feed on various plants.

Diet in Aquariums

In aquariums people tend to feed goldfish with;

  • Goldfish specific food. These feeds contain more carbohydrates and less protein, which is what is needed.
  • Peas whose outer skin is removed.
  • Bloodworms.
  • Green leafy vegetables.
  • Brine Shrimp- this is mostly fed to the young ones.

Feeding Schedule

Feeding your goldfish is not all about giving them food; it also comes with specific rules you need to adhere to. Failure to do so may lead to numerous problems.

Do not overfeed your goldfish

Goldfish cannot stop eating on their own because they are opportunistic eaters. That is why it is your role to feed only the right amount of food to them.

In the event that you overfeed them, their intestines will block. This mostly happens to goldfish with convoluted intestinal tracts. In such cases, these goldfish produce more waste due to incomplete digestion.

Pre-soak flaky food

Make sure that you pre-soak flaky goldfish food before giving it to your goldfish. Naturally, goldfish are bottom-feeders. Therefore, when the food is at the top, the goldfish will gulp.

Doing so upsets their swim bladder and, eventually, their equilibrium. This then makes them float/swim upside down.

Water and Tank requirements

Seeing the lengths in which goldfish can grow, it is advisable to start with a relatively large tank. Its size can range from 75 to 100 gallons.

It is true that goldfish can withstand very low temperatures. However, that does not mean they can live in such conditions forever. Therefore make sure that the water in a goldfish tank is 67 °F or thereabout. The alkalinity of the water should be between 7.0 and 7. 4.

One thing that is necessary for a goldfish tank is a filtration system. This is because goldfish generate a lot of waste that needs to be dealt with.

You can also add a substrate at the bottom of the tank. Although most tanks use sand gravel, it is not advisable to use here. The best substrate to use in a goldfish tank is pea gravel. This is because it is easy for the goldfish to consume as they slurp bits of food from the bottom.


There is a wide range of fish and other water animals that can live with goldfish. Here are a few examples:

You should avoid keeping aggressive or very sensitive fish with goldfish: barbs, angelfish, discus, betta fish, livebearers.


Breeding for goldfish is one of the most exciting things in the aquatic world. Before we get to breeding, you need to know how to differentiate a male from a female.

There are many ways of doing so, but here are some few tactics.

Look at the Body Shape

  • Females: Female goldfish have thicker and rounder body shapes than males.
  • Males: Males have thinner and streamlined body shapes.

Look for the Vents

  • Females: The anal opening (also known as vent) is usually rounder in females.
  • Males: Males usually have concave vents.


  • Males: Males usually have small white spots on their gill shields; that is what we call tubercles.
  • Females: Females do not have tubercles.

How Goldfish Mate?

The goldfish first chase each other until the female lays eggs. The males then release milt, which fertilizes the eggs. The babies hatch in a week or two at most.


If you thought having goldfish is easy, by now, you know it is quite tricky and challenging. You need to have proper knowledge of feeding and caring for them. For instance, for you to keep the goldfishes’ color, you need to provide good lighting.

If you do not do this, they may lose it and turn white. Another fact is the fact that they just need the right quantity of food, not too light and definitely not too much. These are just some of the basic things to help you navigate the world of goldfish.

Updated: March 2, 2020

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