Why is my fish tank always full of green?

Everyone in the process of raising fish will encounter a troublesome problem: the water in the fish tank will always turn green!

Why? In general, the real reason why the water in the fish tank turns green is algae flooding.

  1. Too much light time in the fish tank, resulting in a large number of green algae biological reproduction and growth. Floating in the water, adhering to the fish tank wall or aquatic plant leaves surface, making the water green.
  2. The ratio of fish and aquatic plants in the fish tank is not reasonable, and the capacity of the fish tank is too dense. Resulting in the filter can not completely filter pollutants, is the water quality environment is polluted, but also make the green algae organisms grow too fast.
  3. Feeding too much, a lot of fish food in the water decay and deterioration, and this is the nutrients of green algae, so it will grow more green algae, let the water of the fish tank become green.


There are different kinds of algae in fish tank: such as green algae, blue-green algae, black hair algae, filamentous algae, moss, etc. For the proliferation of these algae, we  need to prevent and solve them.


How to prevent and solve the fish tank algae flooding?

  1. 1.Improve the filtration system:Improve the filtration system in the fish tank to enhance the rate of pollutant treatment in the tank and reduce the nutrients for green algae growth, thus slowing down the time for the water to turn green. You can use a filter with germicidal lamp to effectively reduce green algae and purify the water, or buy a UV lamp directly to use in the existing filter. We use a JUP02 filter from COOSPIDER, and it works very well! There are many germicidal lamps on the market, but I think the following mini UV lamp is great, small and effective in removing green, and can be used in many types of filters.

    Link for 4 in 1 Filter: https://www.amazon.com/dp/B08HRRJCKG

Link for Mini UV Lamp: https://www.amazon.com/dp/B09GLTHWQN

  1. Biological control: Replace new water for fish in time. It is very effective to breed some algae natural enemies to control algae. You can breed some algae eating fish and snails and shrimps in the aquarium to establish a food chain that simulates nature in the aquarium. This organism that feeds on green algae can effectively reduce the number of green algae.Aquatic plants as much as possible to plant some, so that the aquatic plants in the water body of nutrients absorbed sufficiently, there is no algae flooding conditions.


  1. Shorten the light time: Should pay attention to never place the fish tank in the sunlight to the location. Also pay attention to the use of light. Too much light, too long, is also the cause of the growth of algae, green algae lack of sufficient light, it will slow down the growth rate, the number will also be reduced. You should arrange the lighting level according to the size of your tank. After all, the lighting level is easy to control, the normal lighting time should be controlled at about 10 hours.


  1. Prevent in advance:Before you set up the new tank, you should do prevention Before planting aquatic plants, add algae and moss remover to the water, about fifty percent of the normal usage. Secondly, when you buy aquatic plants, first of all, look at the surface of the aquatic plants whether with algae. If there is algae on the foliage, give up as much as possible. For some aquatic plants that have been purchased and found to have a little algae, you should gently wipe your hand on its surface, clean it and then soak it with 50% of the proportion of moss remover for about 3-4 hours.


  1. Make the habit of daily observation: Learn to observe the health condition of aquatic plants and ornamental fish at the same time. Once you find spotted algae, filamentous algae on the bottom or aquatic plant roots or extending to the leaf edge, remove it immediately.


Next time, we will talk more about the physical control methods to get rid of green algae, so stay tuned! If you have any questions, please leave us a message after the article.

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