Helping you keep your aquarium beautiful and healthy


An Aquarium in a Glass Bubble

by Robert W. Bly, founder,

When I was younger, I didn't even think about all the work it took to maintain my aquariums. It gave me pleasure, and I had more energy, and so I just did it.

When you get older, you are busier and have many other demands, so you may look to reduce the work caring for your aquarium.

Now there is an aquarium you can buy that takes literally zero maintenance work. You don't have to feed the specimens, change the water, or even clean the tank.

I am referring to the EcoSphere®, sealed glass containers that contain small aquatic animals (shrimp or tiny fish) and some plants. You can buy an EcoSphere online at I have also seen them for sale in gift shops, but never in fish stores.

How can the plants and animals live in a fully enclosed environment with no access to outside air and food, and no way to remove waste from the environment?

The EcoSphere is a balanced ecosystem: the plant generates oxygen and supplies food. The animal generates carbon dioxide for the plant. Add sunlight, and the plant grows, providing more food for the animal.

I once did an experiment to create a homemade ecosystem that you can do at home too. It requires half a dozen mason jars with lids and some snails and aquatic plants.

In the first jar I put plants only. In the second jar, snails only. In the third jar, an equal number of plants and snails.

The other jars can contain any ratio of animals to plants you want to test; e.g., three plants to one snail; two snails and one plant.

The jars are sealed and observed. Because most of these ecosystems are unbalanced - too many snails in proportion to the oxygen-generating plants or vice versa - they soon break down. The plants and snails die, the water gets stinky and cloudy, and you have a failed ecosystem.

Some of the jars last longer than others. The one that lasts longest - I seem to remember it was four plants and two snails - is the most balanced ecosystem.

But your home-made ecosystem won't last forever. You can leave it sealed, and eventually it will become unbalanced. The death of an animal is usually the cause: the small ecosystem can't rid itself of the waste generated by the animal's decomposing body, and the whole thing breaks down.

The commercially available EcoSpheres are better balanced than my home-made ecosystems and more beautiful, too. But even they don't last forever. The bigger ones are guaranteed to have shrimp alive in the sealed glass container for a full year.

Home-made ecosystems are an interesting experiment and a lot of fun. The commercial ones are quite beautiful, and the price won't break your budget. So for a maintenance-free aquarium in a small space, try a sealed ecosystem.