A natural freshwater aquarium is a great gift idea for children. Plants are the focus of this aquarium; they need carbon dioxide rather than oxygen, so limit the amount of oxygen in the water.
Tools and Materials
Small submergible filter
Full-spectrum florescent light fixture
Natural Aquarium How-To
1. Start with a glass fish tank (we used a 20-gallon tank) with a tight-fitting glass cover.
2. Put a 2- to 3-inch-deep layer of coarse gravel on the bottom of the tank. The gravel should be suitable for growing plants. Make sure the color of the gravel is as natural as possible, since brightly colored types of gravel won't work well visually.
3. Add the plants. Having plants sucking up nutrients helps prevent algae so it's important to select fast-growing varieties. There are several different types of freshwater plants, and they are divided into grasses, rosette plants, stem plants, and ferns. Look for ones with good color, firm stems, and established roots. Remove the plants from the pots, separate any plant bunches, and free-up the roots. Choose different colors and textures and plant them so that the taller plants are in the back and the shorter ones are in the front of the tank. Plant them deep enough so that the crown of the plant is just above the gravel bed.
4. For this aquarium, you don't need a strong filter that will cause a lot of turbulence and oxygen exchange in the water. A small submergible filter that causes a gentle current is all you need.
5. The plants for the aquarium come from tropical areas, so you'll also need a submersible heater to keep the water at 78 degrees.
6. Add enough water to fill the tank about 3 inches from the top.
7. Choose small fish that aren't active or destructive to the plants. Some hardy fish include guppies, platies, and small tetras such as neons and hatchet fish. To help keep the amount of algae down, add a few ghost shrimp and algae-eating catfish to the tank.
8. The plants need light for energy, so you will need a full-spectrum florescent light fixture.
9. A natural aquarium needs very little maintenance. Prune any overgrown plants with a long pair of scissors every once in awhile. Once a month, change 10 percent of the water in the tank. Regular water changes are important for keeping plants healthy since many of the nutrients a plant needs are found in tap water. You don't have to fertilize, but if you want to, some pet stores that carry aquatic plants will carry fertilizer too.