Goldfish (Carassius auratus auratus) are the most well known pet fish and the most commonly kept pet fish. Goldfish were first bred from Prussian carp (Carassius auratus gibelio) in China and are the closest related species to Carp. The goldfish was first domesticated in East Asia over one thousand years ago and since then there have been several breeds developed. They are one of the most hardy coldwater fish to keep as they require very little maintenance and will adapt to even the toughest situations. They can live for over 20 years if cared for properly and given a big enough tank as they can grow over a foot long in length.
Goldfish are generally very passive in behaviour. They are constantly on a search for food so if they are kept in a tank with gravel the goldfish will eat and regurgitate the gravel to check if it had any remnant of food on it. They have a memory span of 3 months and will recognize times when they are about to be fed if they the times are in a regular pattern. My older goldfish especially Ronaldo would become more active whenever I approached them and would even follow my finger as I waved it outside the tank, this was at anytime I approached not just to feed them. In winter when the water was at it’s coldest I noticed the goldfish did not move around as much, the optimum temperature for goldfish is 21°C. Touching a goldfish is harmful to them, like most fish as they have a slime coat which reduces bacterial infection and water-born parasites and it is damaged when humans touch them. At Aquascope.net we recommend you do not pet your fish!
Memory of a Goldfish
Unlike the common misconception that Goldfish have a 15 second memory they in fact have a memory-span of at least three months and can distinguish between different shapes, colours and sounds. Goldfish vision is among the most studied of all vision in fishes. Using positive reinforcement, goldfish can be trained to recognize and to react to light signals of different colours or to perform tricks. Fish respond to certain colours most evidently in relation to feeding. Fish learn to anticipate feeding provided they occur at around the same time every day.
In an aquarium fish will eat the live plants and in the pond they will eat small insects. I used to buy Aquarian’s coldwater fish food flakes to feed my goldfish which can be purchased here: Aquarian Goldfish Flake Food (Pot Size: 200g)
Goldfish may only grow to sexual maturity with enough water and the right nutrition. Most goldfish breed in captivity, particularly in pond settings. Breeding usually happens after a significant temperature change, often in spring. Males chase gravid female goldfish (females carrying eggs), and prompt them to release their eggs by bumping and nudging them.
Goldfish, like all cyprinids, are egg-layers. Their eggs are adhesive and attach to aquatic vegetation, typically dense plants such as Cabomba or Elodea or a spawning mop. The eggs hatch within 48 to 72 hours.
Within a week or so, the fry begins to assume its final shape, although a year may pass before they develop a mature goldfish color; until then they are a metallic brown like their wild ancestors. In their first weeks of life, the fry grow quickly—an adaptation born of the high risk of getting devoured by the adult goldfish (or other fish and insects) in their environment.
Some highly bred goldfish can no longer breed naturally due to their altered shape. The artificial breeding method called “hand stripping” can assist nature, but can harm the fish if not done correctly. In captivity, adults may also eat young that they encounter.