Goldfish – The Care, Feeding and Breeding of Common Goldfish

The goldfish is by far the most commonly kept fish, inhabiting fish bowls and ponds worldwide. Nearly everyone has owned a goldfish at some point in their lives, and countless children have excitedly brought home a small plastic bag containing a goldfish. But for such a common fish, they are rarely kept in anything approaching a healthy environment.

Your goldfish does not want to live here


The first thing that someone new to goldfish needs to know, is that they need a lot of space. Those small fish bowls you constantly see goldfish in are far too small for a goldfish to survive in for more than a few weeks. Goldfish are a wide body fish, love to eat and are very prolific poopers. After a few days of  eating, pooping, and then eating some more, the built up waste in a fish bowl will turn toxic – and then you have a dead goldfish on your hands.

So now we come to the question – what should goldfish live in? Goldfish are social animals, so you should be prepared to keep at least three together. If you’re starting with small or fancy goldfish, a 10 gallon fish tank with strong filtration is a good start. But you need to know that common goldfish grow up to 12 inches, and fancy goldfish usually grow to around 6 inches.

With fancy goldfish you can  happily house adults in a 29 gallon fish tank, but common goldfish are going to need at least 55 gallons to be happy and healthy. And these tanks are going to need good filtration. Since goldfish are such messy fish, a good HOB (Hang on back) filter or sponge filter is usually the best and most affordable way to go. If you have some spare money lying around, nothing beats a canister filter on a fish tank.


Goldfish are not hard to please in the food department. While many fish species have specific food needs, with some only accepting live food, and others turning their noses up at anything resembling flake food, goldfish will happily eat anything you give to them. That’s not say that you should feed your goldfish anything – but you won’t every have a hard time getting them to accept it.

In the wild goldfish have a lot of algae and plant matter in their diet. The key to a healthy goldfish is to mimic this diet as much as possible. A goldfish should be feed a high quality flake food daily, and as an occasional treat they can be fed frozen foods like blood worms, daphnia and brine shrimp. This base diet should be supplemented with vegetables like zucchini nd shelled peas. Many sick, bloated goldfish (fancy ones especially) have been cured with a single serving of shelled peas.

A good way to keep vegetables handy is to cut up a zucchini into medallions and freeze them until you need them. Before serving one to your goldfish, just boil it in bottled water until it’s soft, allow to cool and then serve. Peas are equally easy. Just boil the peas for a few minutes, allow to cool and squeeze the peas out of their shells directly into the fish tank.


  1. says

    Very informative!

    “In the wild goldfish have a lot of algae and plant matter in their diet. The key to a healthy goldfish is to mimic this diet as much as possible.” – I second that! Because goldfish are primarily plant-based, I like to feed my goldfish special “treats” twice a week, which usually consist of seaweed, boiled veggies, or a freeze-dried meal.

    I’ve also been considering adding live plants to the tank – something for them to munch on time and again. I heard goldfish really like duckweed!

    Terrific read! I’m definitely going to share this.



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