03 Jul MYTH BUSTING: “GOLDIE” DOESN’T (JUST) EAT FLAKES
The goldfish (Carassius auratus) is the species of fish most commonly kept as a pet. On top of the great variety of shapes and colors, which make them very attractive, they are animals that can live more than 10 years and they can easily bond to their owners.
The species was obtained by selecting the orange and red individuals that were accidentally obtained during the commercial breeding of different species of asian carp in China, between the third and fifth centuries (Jing Dinasty).
It is an omnivorous species, for which specific requirements have not been detailed, although information on dietary requirements have been stated for a close species (the common carp, Cyprinus carpio) and some work has been done regarding its intensive beeding (therefore more oriented to optimise growth and reproduction than health and longevity).
This lack of information and the fact that nutrient digestibility levels for ornamental species hampers the production of complete formulated diets, as it happens with cats and dogs commercial diets.
A natural diet improves the fish color, increases the nutritional value of the diet and provides nutritional enrichment to fish
This is why it is advisable to combine more than one brand of commercial food, and supplement with a natural diet as often as possible: Spirulina, lettuce and other green vegetables, green peas (without the hard skin), boiled veggies, Daphnia, Artemia, mosquito larvae, etc.
A natural diet improves the fish color, increases the nutritional value of the diet and is a way to provide nutritional enrichment to fish.
Commercial fish food should be pelleted or extruded, since it has been proven that flakes quickly lose their water soluble vitamins (up to 90% of the cyanocobalamin in 30 seconds!!!, Pannevis 1994). Furthermore, goldfish do not naturally find their food on the surface, but eat whatever is in front of them; some authors have linked the use of this type of diet with swimming bladder problems in tis species.
Fish diets don’t have an expiry date, so it is reccommended that the food is discarded six months after opeinig the package (three months according to some authors).
Tips to feed fish
Since they lack a real stomach, it is advisable to offer food at least twice a day.
The higher the temperature (i.e. during summer) the more food they’ll eat.
The whole serving must be eaten within 5 minutes.
The serving must be reduced if there is any leftover food.
The serving should be increased if the fish are too thin (sunken abdomen, loss of dorsal muscle mass).
The size and age of the fish, natural food availability, temperature and type of diet are factors that can affect the amounts and frequency of feedings that a goldfish needs.
If you’d like to read more about this subject, you can find an article in this link (in spanish).