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The Goldfish Gazette, Issue #068 -- Growing Goldfish Fast
August 29, 2019

Goldfish Care Tips

A Free Monthly Resource For Goldfish Enthusiasts
August 2019
Issue #068

In This Issue
Growing Goldfish Fast

Large Goldfish look far more spectacular than smaller specimens, especially the fancy varieties with their long flowing fins, large wens and other bizarre attributes.

Growing Goldfish Fast

I have been seeing a number of posts on social media showing before and after images of fish that appear to be growing extremely quickly, and the questions about how this was being achieved.

Most fish available from retail outlets are usually small and very young, and are priced accordingly. Larger specimens can command very high prices, especially if they considered high quality. In Asia, show winning fish fetch tens to hundreds of thousands of dollars.

These show winners are always large examples of their type, as smaller fish don’t win as many points as do the larger ones, just because they don’t look as graceful and majestic.

How Asia Grows Goldfish Fast

To learn how to get Goldfish to grow large fast, we only need to look at how it is done in Asia.

In Asia, once a fish has been selected as a possible show fish, it is given its own pond, and provided with food continuously.

These fish grow extremely quickly.

It is reported that these fish often have shorter lifespans, and don’t spawn as readily as slower grown fish. Perhaps, because of the feeding program, the fish become over-weight?

Most of us don’t want to grow our fish large for show purposes, but we do want them to grow to a reasonable size, reasonably quickly and not be stunted.

There are some advantages growing them quickly because when they slow down or stop growing, fins and other attributes continue to grow. These often hinder feeding and mobility.

The Magic Formula to Grow Goldfish Fast

1. Health – The fish must be in perfect health. Because the fish we want to grow are usually small, they are more susceptible to parasites such as flukes.
2. Space – Even though we may keep their water pristine, the more space Goldfish have, the bigger they seem to grow.
3. Water quality – it goes without saying that high water quality must be maintained at all times. Frequent water changes remove growth inhibiting hormones given off by the fish. The more frequent the water changes, the faster Goldfish grow.
4. Food – High protein food, around 40-45% is required, and fed frequently, at least two times a day. Growth comes from food. The more food the fish eat in the shortest amount of time, the faster the growth rate. Feeding what can be eaten in two minutes will not be enough for fast growth. Ideally, there should always be food available.
This is when dry prepared foods can cause digestive problems when being fed in quantity to fancy varieties. Gel foods are more suitable when feeding for fast growth.
5. Temperature – Water temperatures need to be above 20oC (68oF) before Goldfish start to grow quickly. If a fish is kept at 26oC (79oF), it will be twice the weight after 30 days than if it was kept at 20oC.

Goldfish grow fastest during the first year of their lives. By the time you buy them from your local fish store, they may already be 6 months old or older.

After 12 months Goldfish on average grow about 1 inch (25mm) a year, which is quite a slowdown from 3/16 (4.5mm) to 3 inches (75mm) in the first 6 months.

You can only guess how old fish are by their size, and using the breeding season as a milestone. If males are showing breeding tubercles, they are at least 12 months old.


Goldfish grow fastest during the first 12 months of their lives. The younger they are when you buy them, the better.

The combination of excellent health, space, high water quality, high protein food and higher water temperatures are all required to achieve maximum growth.

Because of the heavy feeding required, waste management (water changes) become extremely important.

Comments? Ideas? Feedback? I'd love to hear from you. Just reply to this e-zine and tell me what you think, or what topics you want covered.

Next Month's Topic

How to Sex Goldfish (out of breeding season)

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