Feeding by Weight

by Gwynneth
(Hereford, UK)

I saw on the internet, a while ago, a chart that showed how much food (in grams) a fish should be fed, by its own weight/length. I now can’t find the chart.
The common idea seems to be to feed what can be eaten within 2 minutes, but this poses a couple of problems
1) my fish don’t eat when I am there
2) some of my fish are slower at eating - although RIP doesn’t eat when I am there he is always on the lookout for food. I’m sure none of the others get a look in.

I am soon to introduce some more fish (once they are out of quarantine) and these range from 4cm - 10cm. RIP is approx 18cm.

Will there be enough food in the pond, which was set up last year and already has pond skaters and diving beetles, to sustain these tinies? I am currently feeding 5-6 pellets to the newbies (5 x 4cm, 2 x 8cm and 1 x 10cm). Again they don’t eat when I am there but there are never any pellets on the bottom a few hours later, which there was when I first got them three weeks ago.

Should I slowly up their feed until I see some left and then cut it back by the number of remaining pellets?

How many pellets should RIP be having if fed only once a day?

Many thanks for any answers.

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Grant's Reply


Hi Gwynneth

The common idea of feeding fish no more than they can eat in two minutes doesn’t really work for Goldfish because of the way they eat, and because they only have a rudimentary stomach.

You don’t say how big your pond is, so I can’t comment on whether there is enough natural food present, but generally, unless the pond is very large you need to feed the fish.

Size is everything in the fish world, the biggest always gets the most food. You have a large size difference between the smallest and RIP. RIP will continue to dominate the others at feeding time.

Now to the difficult question, how much to feed.

The actual amount to feed depends on whether you are feeding for growth, and the season.

During summer adults should be fed between 0.5-2% of their body weight per day. I feed my adults 1% of their body weight. Younger fish such as yours should be fed closer to 2%.

You will need to weigh a few of your smaller fish to get an idea of their weight. My guess would be the 10cm (body length?) fish would be around 35 grams if your fish is a single-tailed variety.

Fish weight doubles when length increases by 25%, so RIP should weigh about 280 grams, requiring about 3 grams of pellets per day.

If the fish aren’t feeding when you are in the vicinity of the pond, train them to come to you at feeding time.

At the same time and place each day, feed only a small amount of food.

Continue this for approximately two weeks. By the end of the two weeks, the fish will be gathering at the spot looking for food.

Slowly increase the food to the daily amount you have worked out your fish need once all your fish have got into the habit of coming to the feeding spot.