• Aquarium tanks come in all shapes and sizes. The size is determined not only by how many gallons of water it holds, but by the dimensions as well. The smallest rectangular tanks hold 5 gallons of water, but 10-gallon tanks are more common. Aquariums actually range in size up to 180 gallons, but commercial aquariums can be much larger. In addition, aquariums are made of either glass or acrylic. There are also numerous uses for aquarium tanks besides holding water for aquatic life.
  
  

Fish

• The most common and usual use for an aquarium is as a fish tank, either saltwater or freshwater. For beginners, a smaller tank is advisable because it is easier to maintain. A filter is a necessity to clean the water of impurities such as leftover food and waste products from the fish. You also need a cover to prevent fish from jumping out and to keep out objects or predators like cats. Some other necessities are a fluorescent light, gravel and various plastic or live plants and statues for the fish to hide in or under. Water must be completely dechlorinated before fish are added. It is important to choose fish that cohabitate well, or they could end up fighting and attacking each other.
  
  

Reptile Habitat

• An aquarium is not only for fish. A tank makes an excellent habitat for reptiles such as snakes or lizards. The first step in setting up a reptile habitat is determining how large the reptile will grow. Small reptiles like chameleons will only need a relatively small tank, maybe 10 gallons, but a large lizard like an iguana or monitor lizard will need a very large tank, 100 gallons or more. Many lizards and snakes like to climb, so including a few branches will keep them happy. A locking lid is a must, because lizards or snakes could manage to open a flimsy lid. You can use gravel in a reptile tank, but sand is preferable because if the reptile accidentally eats the sand, it will not get stuck in their gut. Reptiles are cold-blooded, which means you will have to have a heater and light in the aquarium. A hot rock is a heated stone that is buried just beneath the sand and will keep the reptile warm enough that its digestive system will work.
  
  

Plant Terrarium

• An aquarium tank is a great place to grow small plants. You can design the terrarium, which is like a mini-ecosystem, will any number of plants. The plants do have to have similar needs, such as plants that like dry conditions or plants that like wet or moist conditions. This is because the terrarium is an enclosed space and will not allow for multiple conditions. Terrarium plants must like humidity, because the plants are in close proximity to one another and will create their own micro climate by their transpiration process, releasing moisture or dew from the pores in their leaves. A terrarium needs shaded conditions, but it also needs partial sun or a UV lamp.