1. Small fish that are easy to raise and live in ecological bottles. It is difficult to raise a big fish like goldfish. In addition, some loaches can be properly raised. Creatures such as shrimp and snail can also be added. Aquatic plants are essential creatures among them. The water put into the ecological bottle should not be tap water, but water rich in organic matter filtered from the lake, which contains plankton needed by fish. In the ecological tank, fish can go to the river to collect some jellyfish, goby and goby, catch Macrobrachium nipponense (a very common transparent shrimp) to make shrimp, and the shrimp can eat feces and dead fish. Small fish+Ceratophyllum is also good.
In fact, fish can't adapt to the new environment. Most fish are very sensitive to sudden changes in water temperature. When the fish is suddenly replaced by water with different temperature, it is easy to die naturally. Therefore, it is also important to put fish in ecological bottles. You can put a plastic bag in the original water tank where the fish is located, transfer the fish to this plastic bag, and then transfer the water and fish together to the ecological bottle. After about 1.5 hours, you can rest assured.
3. How many fish should I put in an ecological bottle? The number of fish preserved in ecological bottles is directly related to the volume of water in ecological bottles and the amount of oxygen that fish can get in water. If you keep goldfish, it is enough to put two or three adult goldfish every 4 liters of water. Another way to judge whether there are too many fish in an ecological bottle is to pay attention to whether there are any fish floating on the water and constantly "panting". If this happens, it means that there is not enough dissolved oxygen in the water, or there is something wrong with the water quality or too many fish are put in.
4. Snails, small fish and shrimp are hard to eat by children in the city, so water snails can be used instead. Generally, one or two water snails can be put in a 20-liter bottle. Water snails breed quickly, and soon you will find colloidal eggs on the bottle wall or on the water. Within two weeks, you and your students will observe that eggs begin to hatch into small snails. Water snails mainly feed on green algae. Green algae is a green film-like substance that grows on the bottle wall. Note that the amount of sunlight received by the ecological bottle is directly related to the growth rate of green algae. In a balanced ecological bottle, the amount of green algae added every day should be similar to that eaten by water snails.