Goldfish are omnivorous fish that require a diverse diet for optimal health. Alongside traditional foods like flakes, earthworms and freeze-dried food sources such as brine shrimp pellets or freeze dried food products there are also fresh fruits and vegetables which should make up part of their daily meal plan; however, fresh food should only comprise a small percentage. When feeding fresh food to goldfish it must always be properly prepared to avoid complications in digestion.
Flakes are the primary food for goldfish and should be given in small doses throughout the day, pre-soaked to prevent your goldfish from swallowing air bubbles when eating the flakes and creating swim bladder issues.
Earthworms are an easy and healthy source of protein to find at pet stores, making them perfect for feeding as snacks or supplementing flakes for extra nutrition. Just remember not to give your goldfish mammalian fats, as this could lead to digestive issues and liver deficiencies in the long run.
Gel foods offer another excellent food option for goldfish. Aim for those made with high quality ingredients like krill, whole menhaden and spirulina instead of generic fish meal (ground up waste products of fish processing used as human food). In addition, these gel foods should have low raw ash contents since too much ash could pollute an aquarium environment.
Pet stores carry readily-available brine shrimp, blood worms, tubifex worms and daphnia for goldfish to supply all the essential vitamins and minerals they require for healthful development. You should offer this treat once or twice every week as a reward to ensure optimal performance from your fish.