Content

• To step
• Part 1 of 3: Collecting the right materials, plants and animals for your ecosystem
• Part 2 of 3: Installing your aquatic ecosystem
• Part 3 of 3: Maintaining your aquatic ecosystem

A closed aquatic ecosystem is similar to an aquarium, except it is cut off from the outside world, so that all necessities of life must be provided by the animals and plants in the system. Most of the species that are suitable for such ecosystems are not that big or colorful, so if you thought of building an ecosystem with all kinds of beautiful fish and plants, you better set up a regular aquarium. However, if you're interested in creating a maintenance-free water world that will stay alive for months, or even years, read on!

To step

Part 1 of 3: Collecting the right materials, plants and animals for your ecosystem

1. Decide how to shut down your ecosystem. The more cut off from the outside world your aquatic environment is, the more difficult it will be to create a self-sufficient one.
   • Hermetically sealed systems are completely cut off from the outside world. Plants and animals must be small and few in number to survive.
   • Closed systems allow the exchange of gases and light (for example through a sponge set in the opening). Gas exchange helps to regulate the pH of the water and allows for the removal of nitrogen and the introduction of carbon dioxide, making these systems easier to maintain.
   • Semi-closed systems require some maintenance. All closed systems will eventually die. You can keep your system running longer by changing 50% of the water every month. This removes dirt and adds nutrients. You can change the water more often if your system is going down.
2. Decide whether you want a fresh or salt water system. Fresh water systems are much easier to build and maintain. Saltwater systems are less stable, but allow for more interesting fauna, such as starfish and annemones.
3. Buy a clear glass, or plastic, jar to house your ecosystem. Weck jars, 2 liter plastic bottles, pretzel jars or carboys from 11 to 20 liters are all suitable. For beginners, a smaller system is easier to maintain.
   • For hermetically sealed systems, you need a container with a tightly fitting lid. For closed systems, you can seal the opening with a cheesecloth or plug it with a sponge.
4. Find a substrate for the plants to grow in. You can buy substrate from the store or collect mud from a pond (which is already home to many of the small creatures you need). For clearer water, you can sprinkle a layer of sand over the mud or substrate.
5. Buy aquatic gravel or get gravel from a pond. The gravel layer will provide a surface for a microbial community, it will also act as a filter and trap the particles as gravity pulls the water down through the gravel.
6. Use filtered water, pond water, or aquarium water. Aquarium or pond water is best, as these already contain the necessary bacteria. If you are using filtered water, you must first let it sit for 24-72 hours for the chlorine to evaporate.
7. Choose your plants or algae. Plants provide food and oxygen to your ecosystem. You need plants or algae that are strong and grow quickly. You can collect or buy these from a pond. Some plants to consider are:
   • Hauwmoss (freshwater) - Very strong. Needs dim light.
   • Fountainweed, or waterweed (freshwater) - Strong. Needs dim light.
   • Spring moss (freshwater) - Less strong. Prefers cooler temperatures.
   • Bladderwort (freshwater) - Delicate.
   • Caulerpa Weed (Saltwater) - Strong, in so far as it can become a pest.
   • Rock seaweed (salt water) - Requires high levels of calcium.
   • Valonia ventricosa (saltwater) - Strong, in so far as it can become a pest.
8. Choose your animals. Animals eat algae and other waste, which keeps your ecosystem clean. They also produce carbon dioxide, which the plants need to survive. Start with only 1 or 2 larger animals, or 10-20 hyalella. WARNING: Fish are not suitable for a closed ecosystem. If you do post them, they will die. The following animals are more suitable:
   • Fire shrimp (freshwater).
   • Slender tubercle horns (freshwater).
   • Hyalella (freshwater / saltwater depending on the species).
   • One-eyed crayfish (freshwater / saltwater depending on the species).
   • Asterina (salt water).
   • Aiptasia sea anemone (salt water).

Part 2 of 3: Installing your aquatic ecosystem

1. Place the substrate (soil) on the bottom of the container. If you're using a container with a narrow opening, you can use a funnel to keep it from becoming a mess.
2. Plant your plants in the substrate. If they float after you add the water, you can put more sand and gravel on the substrate to keep them rooted.
3. Add a layer of sand and then a layer of gravel. Cover all exposed soil, but be careful not to crush your plants. The substrate, sand and gravel together should fill 10-25% of the container.
4. Add water. Remember, if you are using filtered water, let it sit for 24-72 hours for the chlorine to evaporate. The water should fill 50-75% of the container. Leave 10-25% empty for oxygen.
5. Add animals. Before adding animals, acclimate them to the water temperature by letting the plastic bag they are in float on the surface of the water for several hours. Remember: start with just 1 or 2 shrimp or snails, or 10-20 hyalella. Too many animals will kill your ecosystem.
6. Close the container. For a sealed container it is best to use a screw cap or cork, but a piece of cling film with a rubber band will also work, if that's all you have. For a closed container (with gas exchange) you can use cheesecloth or a sponge.
7. Place the ecosystem in filtered sunlight. It should be near a window, but not a window exposed to many hours of direct sunlight, this will cause temperature fluctuations and could kill shrimp and snails. Shrimp, crayfish and snails thrive in temperatures between 20 and 27 degrees Celsius. Your container should feel cool, but not cold.

Part 3 of 3: Maintaining your aquatic ecosystem

1. Keep a close eye on your ecosystem in the first few weeks to make sure it's in the right place. Too much or too little sunlight can kill your ecosystem.
   • If your plants look unhealthy, try giving them more sunlight.
   • If the water is getting cloudy or discolored, try giving more sunlight.
   • If algae develop or if your shrimp die on hot days, try to reduce the amount of sunlight.
   • Be aware that you may need to move your ecosystem based on seasonal changes.
2. Adjust the amount of plants and animals as needed after the first few weeks. This is important to keep your ecosystem healthy, as you probably won't get the right balance right away.
   • Add more snails or shrimp if algae is growing. It's important to keep algae under control or it could cover the walls of your container, blocking sunlight and killing your ecosystem.
   • If the water turns cloudy, it could mean you have too many shrimp or snails. Try to add more plants.
   • If your animals die, add more plants.
3. Know when your ecosystem is dead. It is useless to keep your ecosystem if it is not working, especially as it can start to stink. Here are some signs that you should empty your ecosystem and try again:
   • A foul, sulfur-like odor.
   • Development of strands of whitish bacteria.
   • Very few, if any, live animals.
   • Most of the plants are dead.