The foods that goldfish should absolutely never eat include chocolate containing theobromine, high-salt foods, greasy foods, spicy and irritating foods, processed foods with preservatives, and spoiled foods. These foods can cause serious harm to the physiological functions of goldfish and the water quality:
Chocolate and Its Products
The theobromine and caffeine in chocolate can damage the nervous system and heart function of goldfish, leading to an accelerated heart rate, rapid breathing, and even death. Even a small amount of chocolate dissolved in water will form an oil film that hinders the exchange of oxygen and pollutes the water quality.
High-Salt Foods (such as Salted Fish, Salted Foods)
The osmotic pressure regulation system of freshwater goldfish cannot withstand excessive salt. It will cause cell dehydration and affect physiological functions.
Greasy Foods (such as Fried Chicken, French Fries)
The oil forms an oil film in the water that covers the gills of the fish, reducing the dissolved oxygen content. Experiments show that oily foods can cause the dissolved oxygen content in the fish tank to drop by 40% within 2 hours.
Spicy and Irritating Foods (such as Chili Peppers, Mustard)
The irritating components will damage the olfactory system of goldfish and trigger inflammation of the mucous membranes in the gills and on the body surface.
Processed Foods with Preservatives (such as Canned Goods, Packaged Snacks)
Preservatives (such as sodium benzoate) will accumulate in the bodies of goldfish, damage the functions of the liver and kidneys, and lead to a decrease in immunity.
Spoiled Foods (such as Rotten Bloodworms, Vegetables)
A large number of pathogenic bacteria will breed, easily causing diseases such as enteritis and septicemia, with a mortality rate as high as 73%.
When accidental ingestion occurs, the following measures should be taken immediately:
Clean up the remaining food and change 1/3 of the water volume.
Disinfect according to the ratio of 1 gram of salt per liter of water.
Stop feeding and observe for 24 hours.
If the goldfish turns on its side, it needs to be sent to a professional pet hospital for treatment.
It is recommended to use special goldfish feed or an appropriate amount of vegetables and fruits for feeding to avoid health risks caused by improper feeding.