What harm does green aquarium water do to fish?

As we know, for fish keeping, water quality is a major influencing factor. Sometimes during fish keeping, we encounter the situation where the water color turns green, and in severe cases the fish in the aquarium are barely visible, or even die! Why is this? Is green water unsuitable for fish to live in? Not all green water is unsuitable for fish; goldfish are very well suited to being kept in green water.

If the water in the aquarium you keep has turned green, it only means that a large amount of algae (green moss) has grown in the water and needs to be removed when necessary. This is because algae absorb oxygen at night and release CO2, which reduces the oxygen in the aquarium and increases carbon dioxide, greatly lowering the dissolved oxygen content of the aquarium water and posing a major threat to the fish's survival. If the aquarium has no large fish, or it is an outdoor fish pond, it is not a big problem, because outdoor fish ponds have strong and long-lasting light, and the green moss cannot be completely eradicated.

In the process of keeping goldfish, we like to let the water turn green, because green water is still beneficial to the fish; sometimes we do not want it to turn green, since green water not only affects the viewing experience but also worsens the living environment for the fish. There are actually many methods to control the water turning green, and here is a brief introduction:

1. Reduce the nutrient level of the water

This is something that even many aquarium experts find a headache. The solution is to change the water (especially for bare tanks), change the water, and change the water again. While changing the water, strengthen filtration and use a powerful nitrifying system to prevent the production of toxic ammonia nitrogen and nitrite.

2. Avoid sunlight exposure

Practice has proven that natural light makes algae grow fastest, especially green moss, which will quickly proliferate explosively. Set up a shade awning to block the light, or use newspaper to shade the sunlight. The fluorescent tubes we use for aquarium lighting can also cause incomplete spectrum due to aging, thereby causing algae reproduction. If conditions permit, you can turn on a UV lamp (ultraviolet sterilizing lamp) in conjunction, irradiating for one to two hours a day; if it is for sunning the water, you can add another two hours, which is also very effective.

I believe some fish keepers should know that keeping goldfish in aged water is very good. Aged water looks slightly green and yellowish in appearance.

Aged water is what we pursue, but therefore, cultivating the water in the early stage of fish keeping is very important. Cultivating water is the process of turning new water into aged water. Green water also has many benefits for goldfish. For example, green water can make the goldfish's body color deeper, but if there is too much algae in the water and the fish cannot be seen, then it is not suitable for viewing. Moreover, when there is too much algae, the fish will lack oxygen, so when using green water to keep goldfish, you must pay attention to controlling the algae content in the water. It requires skill.

That is all for the above content. I hope it can help everyone. If there are any shortcomings, I hope all the seniors can offer guidance~~