The size of fish is related to genetics, and the genetic differences among various fish species are the main reasons for their size variations.
Different fish species exhibit varying degrees of genetic traits; some are genetically characterized by rapid growth and larger size, while others develop slowly and remain relatively small.
Genetic factors also determine fat content, muscle mass, and more in fish, which significantly impacts their overall size.
With a size of 7.9 mm when fully grown, the recently discovered Paedocypris progenetica in Sumatra (Indonesia) has become the smallest vertebrate in the world. Previously, the record for the smallest vertebrate was held by the dwarf white-bait fish from the Indian Ocean (scientific name: Trimmatom nanus), which measures 8 mm when fully grown.
The growth and development of fish are also influenced by environmental factors, including water temperature, water quality, light, and water depth.
Environmental factors such as suitable water temperature, light, and depth can promote healthy fish development; unsuitable conditions can hinder their growth and development, potentially causing diseases.
According to the World Wildlife Fund (WWF), the largest animal in the world is the blue whale in Antarctica. They can weigh over 180 tons and reach an astonishing length of up to 30 meters. The heart of a blue whale is equivalent to that of a small car.
A proper diet is also crucial for the growth and development of fish. Fish require a full range of nutrients such as proteins, carbohydrates, and fats to ensure their growth and development.
If the dietary nutrition is not comprehensive, it will affect the growth rate and development of the fish. Additionally, the quality of food is a key factor impacting the health of fish; poor-quality food can even lead to fish mortality.
Well water is a type of freshwater sourced from underground aquifers. Communities drill wells to access it. Since this water is extracted directly from nature, it often contains various impurities such as nitrates, nitrites, and heavy metals. Moreover, it may harbor harmful bacteria like E. coli, coliform, and pathogens that cause gastrointestinal diseases such as cholera, dysentery, and typhoid.
The method of raising fish also significantly affects their growth and development. Common methods in fish farming include extensive farming, intensive farming, and polyculture. Differences in these feeding methods will impact the growth rate and development of fish.
In intensive farming, fish feed and rearing environments are better managed and regulated, leading to faster growth.
So why do fish in wells not grow?
Well water provides a unique environment for raising fish, and due to environmental constraints and rearing conditions, the growth rate and space for fish development are severely limited, resulting in smaller sizes and slower growth. Specifically, the limitations of well fish farming are as follows:
Space limitations: The size of a well is often restricted, leading to a relatively small number of fish that can be raised and limited space for each fish to grow.
Compared to breeding in open waters, fish in wells face more competition for food and space, which hinders their growth and development.
Insufficient food: The food supply in wells is relatively limited, primarily relying on artificial feed. If they do not receive sufficient nutrition to meet their needs, the growth rate of the fish will naturally slow down.
Fish are vertebrates, mostly ectothermic, possessing gills and living in water. Currently, there are over 31,900 known species of fish, making them the most diverse group of vertebrates. Goldfish are often among the longest-living ornamental fish that we can keep as pets. With proper care and ample space, they can grow significantly large and live for a long time. On average, goldfish live between 10 to 25 years, with some examples even exceeding 25 years.
Unstable environment: Due to the relatively closed nature of well water, it is challenging to control environmental conditions such as light and water temperature, which over time can reduce fish immunity and make them susceptible to various diseases.
Furthermore, wells can experience water pollution and other issues, affecting the growth and development of fish.
The size of fish is influenced by many factors; genetics, environment, food, and feeding methods are closely related to their growth and development.
Although fish in wells can survive in a closed environment, the limited conditions significantly restrict their growth and development processes.
Therefore, to promote better fish growth in wells, it is essential to provide a better environment, more diverse food, and more scientific feeding methods.
