Aquarium tanks that hold between 15 - 40 liters (4 - 10 gallons) of water are considered miniature aquariums or mini-tanks. This is not an ideal aquarium for children or beginners, and will require a bit more work than a larger aquarium to maintain great water quality.

There are specific problems with the water in a mini-tank because it becomes murky much more quickly and needs more frequent changing than a larger tank. However, one of the advantages of the mini-tank is the limited amount of water. When you want a tank that requires very expensive soft water, the mini-tank is the ideal solution. Fish that depend solely on live food are more easily kept in a miniature tank, as live food is not always available year-round.

With a smaller tank, you can be more selective about the amounts you feed. You need to remember that the smaller amounts of water required in these miniature tanks are not as constant as the larger amounts in standard aquariums.

Stocking a miniature aquarium can be a great deal of fun, as there are some fish that are so small they would virtually disappear in a large aquarium. Some of these miniature aquatic denizens include:

*Heterandria Formosa: As a rule, they only grow to about 3 cm, with the male being 1 cm shorter than the female. These tiny fish are much happier in a dedicated aquarium like the miniature tanks that we are discussing here.

Delicately branched plants such at the Myriplhyllum or Caboma are ideal here, as it allows you to easily view your "killifish." They should be given crumbled dry food and offered brine shrimp between feedings. Water temperature and light are not a big consideration for these live bearers, and their young will grow up just fine without our help.

*The everglades pygmy sunfish, or Elassoma evergladei have the same minimal demands as the previously mentioned killifish, but eat only live food. These young will grow up without our intervention. The black males with blue spots are very captivating during their courtship dances.

These are just two of the fish that will thrive in a small aquarium with little or no additional lighting and heat.

A Paludarium for Your Mudskippers

A pauldarium is simply an aquarium that also has land and roots for the mudskippers to climb on. To set up this tank, you need to keep it simple so it is easier to maintain. An aquarium with a bottom of 40 x 120 cm is large enough for 5 or 6 fish. Because they are very good climbers, the top should be tightly covered to keep the fish from escaping! In addition, the air must have very high moisture content; which, can only be achieved in a covered aquarium. The temperature of the aquarium should range between 25 and 30 degrees centigrade. The water content is not of major importance because mudskippers live in the tidal regions of rivers. While they can live in fresh water, it is best to add some salt -- about 1 tablespoon per liter of water.

The paludarium needs to have a sizable land portion, with flat rocks placed sideways, and a substrate of 10-15 cm. While you can use Cryptocoryne affinis as decorations, the terrace should be left mostly without plants. After the rocks and roots have been placed, use sand and gravel to create the bottom of the tank. In the water area, the substrate should only be 2-5 cm.

The lower part becomes the water area with a few large pieces of rock should stick out of the water. A large root may also be provided. The water area should be planted with only one large fern in the corner.

Mudskippers are actually fish and they have eyes that protrude way beyond the sides of their heads. These fish live in the mangroves and low palms of estuaries and lagoons and usually crawl around on the muddy shallows on their pectoral fins. They can live either in or out of the water. They occasionally climb up the roots to have a look around, but because they are actually fish, they also need to return to the water frequently to keep their gills and skin moist.

When breeding, mudskippers establish territories that they jealously guard against fish of their own species. They lay their eggs in mud holes that they have dug. This explains why breeding mudskippers have never been accomplished in an aquarium.

These unique fish are wonderful to observe, and maintaining your pauldarium will be a simple and enjoyable process.

A Small Home for the Dwarf Cichlids

Dwarf cichlids are another breed of fish especially suited to small aquariums or mini-tanks. While it is not necessary to have only one species of small fish in a mini-tank, you will want to speak to your pet store manager for advice on which fish can be put in the tank with the dwarf cichlids.

A "scree," or rocky aquarium, is ideal for the dwarf cichlids and are quite attractive. This type of aquarium consists of about ¼ rocks. These fist-sized rocks are round and piled in the aquarium, where they nearly reach the surface in the back and about halfway up in the front. Delicate plants are planted in a free spot in the foreground, center of the tank.

Providing a couple of rock caves will allow you to observe the courtship, mating, and care for the young, since these fish do not eat their babies. Wedge the rocks tightly so they don't fall over or become dislodged from their design. Some prefer to glue these rocks together with rubber silicone during installation; however, if this is done, they need to be allowed to dry for at least two weeks before the aquarium can be filled with water.

The rocks should be placed directly on the bottom of the aquarium; then the sand is added. Another means of decoration for the dwarf cichlids would be to use slabs of slate, creating cracks and caves for the fish to hide and breed in. With the dwarf cichlids it is not necessary to provide companion fish, as they are quite content to be with their own species. Because of this the young cichlids can grow up with little of no attention from us.

Add to these fine leafed and delicate plants, and you will have a mini-tank that will bring you hours of pleasure as you watch your dwarf cichlids populate their new home.