About feeding a goldfish
Goldfish are cool-water cyprinids that grow far larger than the bowl myth suggests and are prone to constipation and swim-bladder problems from overfeeding floating flakes.
How much should a goldfish eat?
Aquatic feeding is measured as a share of body weight per day, adjusted to the two-minute rule. The chart below uses about 0.8% of body weight daily.
| Body weight | Food per day (~0.8% of body weight) |
|---|---|
| 50 g | 0.40 g/day |
| 108 g | 0.87 g/day |
| 167 g | 1.3 g/day |
| 225 g | 1.8 g/day |
| 283 g | 2.3 g/day |
| 342 g | 2.7 g/day |
| 400 g | 3.2 g/day |
What to feed
Goldfish do best on sinking pellets and gel foods with plenty of plant matter (blanched peas, greens). Their lower metabolism means they need less than tropical fish.
How often to feed
Feed small amounts once or twice a day, only what they clear in about two minutes, with a weekly fasting day.
Frequently asked questions
How much should I feed a goldfish?
Only what it eats in about two minutes, once or twice a day — roughly 0.5-1% of body weight. Overfeeding and floating flakes cause the swim-bladder problems goldfish are famous for.
Why does my goldfish float or struggle to swim?
Often swim-bladder trouble from gulping air with floating food or from constipation. Switch to soaked sinking pellets, add fibre like blanched peas, and don't overfeed.
How much should I feed my fish?
Only what they finish in about two minutes, once or twice a day — usually a pinch. As a rule of thumb, most community fish eat around 1-1.5% of body weight daily; large slow fish like goldfish need less.
How often should I feed aquarium fish?
Once or twice a day for most species, with one fasting day per week. Fry and very active small fish need more frequent small feedings.