There are several types of animal life you can add to your tank besides fish. Some aquarium owners enjoy putting small frogs in their tanks. If you have fish that like to nip fins, they may attach the feet of your frog, so be careful. Also, frogs may escape from your aquarium if it is not sealed well.
Snails are another interesting addition to your tank. They can be very colorful and help control algae in your tank. The Apple Snail family has several interesting varieties. The Albino Mystery Snail is a white and yellow snail. The Black Mystery Snail is a very pretty snail that usually comes in a dark black color. Another Apple Snail variety is the Gold Mystery Snail, which is a lovely gold color. Ramshorn Snails have the characteristic curled shell. If you choose to add snails to your tank, keep in mind that then need to breathe air out of the water. Leave some room at the top of your tank for the snail to breathe.
You may choose to have Hammers Cobalt Blue Lobsters in your tank. These creatures are aggressive, so be careful. They sometimes are brown when you first bring them home, because the stress of moving causes them to loose their brilliant blue color. These crayfish stay small in the aquarium, and eat as scavengers on the bottom of the tank. Blue Lobsters are fine with most fish, but avoid putting them with other lobsters.
Freshwater clams can add an interesting aspect to your aquarium. They are filter feeders that reduce nitrates in the water. You may not see much of them, as they tend to burrow into the gravel, but they will help to keep your tank clean.
Shrimp are probably one of the most common invertebrates added to home aquariums. Freshwater shrimp come in several varieties. Singapore Flower Shrimp are a peaceful shrimp that are rosy red in color, but can be brown at times. They grow large, over three inches in length. The shrimp will change colors, perhaps as a camouflage response. Japonica Amano Shrimp are a little smaller than the Singapore Flower Shrimp, and have an appetite for algae, a great benefit for the freshwater aquarium owner. Ghost Shrimp got their name because they are nearly clear in color. They are fascinating as you can watch them as they eat and digest their food. Finally, the Cherry Fire Shrimp is one of the most beautiful shrimp in freshwater tank. They have a bright red coloration and swirling patterns. All shrimp are beneficial to the tank as they are scavengers and feed on algae and leftover food, which helps to keep the tank clean.
Adding invertebrates to your tank makes it more like the natural habitat of your fish. Also, these interesting tank mates will cause your visitors to take notice of your tank. The benefits that the invertebrates give the tank help to keep it clean. When you are stocking your tank, seriously consider adding some non-fish animals to your environment!