Feeding goldfish the wrong food — or too much of it — causes the constipation and swim bladder problems that plague fancy goldfish. The floating flake most people use is part of the problem. The right sinking, varied diet keeps goldfish healthy and buoyant. This UK guide covers the best goldfish foods in 2026.
Here’s how to feed them properly.
- Floating flake makes goldfish gulp air, contributing to swim bladder problems.
- Sinking pellets and gel foods are gentler and prevent most buoyancy issues.
- Blanched vegetables and deshelled peas add fibre that keeps digestion moving.
- Feed small amounts once or twice daily with a weekly fasting day.
Why floating flake causes problems
When goldfish gulp floating flake, they swallow air, which contributes to buoyancy and swim bladder problems — especially in round-bodied fancy goldfish. Sinking food that they eat calmly from the bottom, plus fibre-rich variety, prevents most of these issues.
Our top picks
Best staple — sinking goldfish pellets. Sinking goldfish pellets avoid the air-gulping of floating flake and form a balanced base diet.
Best for fancy goldfish — gel food. Gel foods are gentle on digestion and excellent for round-bodied fancies prone to swim bladder issues.
Best natural supplement — blanched veg & deshelled peas. Blanched courgette, spinach and the occasional deshelled pea add fibre that keeps digestion moving.
How much and how often
Feed small amounts once or twice a day — only what they clear in a couple of minutes. Include a weekly fasting day and offer a blanched, deshelled pea now and then to prevent constipation. Pre-soak any pellets so they don’t swell inside the fish. See best fish food for the wider picture.
Frequently asked questions
What is the best food for goldfish?
Sinking goldfish pellets make the best staple, avoiding the air-gulping caused by floating flake. Gel foods suit fancy goldfish, and blanched vegetables and deshelled peas add helpful fibre.
Why does my goldfish float or sink after eating?
Often because floating flake makes it gulp air, or because it is constipated. Switch to sinking food, pre-soak pellets, add a weekly fasting day, and offer a blanched, deshelled pea.
How often should I feed my goldfish?
Small amounts once or twice a day — only what they clear in a couple of minutes — with a weekly fasting day. Overfeeding is a leading cause of digestive and water-quality problems.
— Jaqline Smalling, FishForever
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