A very common question in goldfish keeping is about goldfish stocking. No, no…this article is not about the garment that you wear on your feet with goldfish motifs, but if you are looking for those, let me help you out. 🙂
Alright, let’s get back to the original intention of this article. I am very sure as a new goldfish keeper, you wonder how big your tank should be. Besides that, if you already got the addiction of buying more and more fish, you would want to know how many goldfish in a tank that you can keep, right?
“Hey! if the fish shop can keep so many in one tank, why can’t we?”, right?
Well… let’s see…
How much space does a goldfish actually needs?
Before we get to that question, let’s take a look at factors that influence the need of space:
Goldfish in general come in 2 body types – streamlined and egg-shaped. Besides the look, these body types affect the goldfish potential size as well.
Goldfish with streamlined body type such as common goldfish, Comet, Shubunkin, and Wakin can grow to at least 12″ in body length which is double the size of their egg-shaped body type counterpart. Examples of goldfish with the egg-shaped body are Oranda, Ranchu, Telescope, and Ryukin.
So in short, goldfish can grow really large!
If they are kept in space that is too small for them, their growth will get stunted and this affects their health tremendously.
Bioload, in general, refers to the amount of wastes produced. If you have not heard about Nitrogen Cycle, please have a quick read about it at this link because this knowledge is CRUCIAL for every fish keeper.
When a fish is considered as having a high bioload, it means that it produces a lot of wastes; and if there are not enough beneficial bacteria to complete the whole Nitrogen Cycle, the tank will turn toxic very quickly. This is even worse with smaller tanks where the toxic concentration builds up much faster.
The goldfish is considered to be one of those aquarium fishes that have very high bioload. Yeap, they do eat, pee and poo a lot!
So based on these 2 factors alone, they are reasons enough that goldfish do require more space.
The recommended stocking for goldfish is at least 20 gallons for the first goldfish and at least 10 gallons each for subsequent goldfish.
This being said, remember that streamlined body type grows bigger than the egg-shaped ones? Well, they will be happier with much larger space… and a pond seems to be a better environment for them.
So how many goldfish in a tank?
Well now that you know the recommended tank stocking which is at least 20 gallons for the first goldfish and 10 gallons each for subsequent ones, it should be easy to gauge how many goldfish you can have in your tank.
Example: If you have 50 gallons of water in the tank, you can keep up to 4 goldfish there.
This also means that you should have at least a 20 gallons tank when keeping a goldfish. A fish bowl is definitely not cool!
If the fish shop can keep so many in one tank, why can’t we?
Well, you have to understand that the fish shop is only keeping their goldfish stock for a short while as they are meant to be sold away.
Besides, most of the goldfish that the fish shops sell are very young and they have workers who do frequent water changes to remove the toxic build up.
Oh dear, I overstocked my goldfish tank. What can I do?
If your current tank is housing more goldfish than recommended, I would suggest the following:
- Upgrade your tank to something bigger. If cost is an issue, you can check out those plastic storage containers that come in bigger sizes but with lower costs. Anyhow, always make sure the tank/container is properly cycled and have a working filter before putting your goldfish in.
- Check and see whether your fish shop is willing to take some back, or sell/give them away to other goldfish keepers.
If your goldfish are still small and you have just slightly overstock the tank (example: 2 small goldfish in a 20 gallons tank), I think you can still keep them with the following conditions:
- have a plan to upgrade the tank within 6 months
- make sure you have a good working filter
- do more regular water changes (2-3 days once)
So that’s it. Hopefully this article gives you an idea on how many goldfish in a tank that you should keep.