The goldfish, being a rather simple pet to take care of are often undervalued in their complexity. Many people think that they grow based on the size of their pond or tank, but this is not the truth. It is true that it has some influence – if you keep it in a small tank, without enough food the effects will be as on every other growing creature – the process will be slower and the life span will be around several years. The maximum size under those conditions is usually between three and four inches, which is around eight and ten centimeters. As this is not so stunning for the size of a goldfish, you see that the process of growing is not influenced significantly in its borders, rather than just slowed.
Things are different when it comes to feeding it too much and keeping the tank without adequate filtering and maintenance. As this creature doesn’t have a stomach the waste is very toxic – an aquarium that is not filtered will lead to poisoning because of the waste or a disease because the water quality is bad. This kind of fishes are genetically predisposed to live in a place with running water so it is very important to change it daily, or to have a good filter.
Given these facts, it is evident that the growth speed of the goldfish is quite different for each case. There are two main factors in that regard – the food you give the fish and the temperature of the pond or tank. As with every other animal, they will grow faster if you give them protein. The healthiest diet for a goldfish has 30% protein in its menu and it should be mostly based on insects and worms, because they are its natural source of protein.
When it comes to the temperature, they grow faster when the water is warm. This is why they grow faster in tanks rather than in ponds, because in the winter it is too difficult to warm the water in the pond, which slows the process. Given that all the requirements are met and the perfect conditions are achieved, the goldfish can reach the very big size of six to eight inches and even more. If you want that just keep them indoors in big heated tanks. They will reach their biggest size earlier and if it is when they are still young and the bodies are “programmed” for growing, the results can be even bigger than expected.
As with the size, the lifespan is also very controversial. The most stunning case is for forty three years – something very uncommon for a goldfish. The statistical average is around fifteen to twenty years in big ponds. In smaller aquariums the life span is way less – between five and ten years. Of course, this depends highly on the filtering and temperature that you choose. If you want to keep them healthy also remember not to put too much food, because it can poison the water if not eaten.
