While invertebrates such as frogs, shrimps and crayfish can be included in aquariums along with fish, they also make interesting pets to keep by themselves in a dedicated tank.

Frogs – there are two types of underwater frogs (they spend their entire lives underwater, never needing to come out) that are normally available. The African clawed frog gets to be fairly large – around 4” or so – and as such can eat small fishes. In a tank by themselves they make very interesting pets. The dwarf frog only gets to be about 1.5” long, and is less of a danger in terms of eating fish. These frogs have webbed front feet, as opposed to the larger African clawed frog, whose front feet are clawed.

Shrimps – there are many ornamental shrimps available these days, and they come in different sizes and colors. The smaller ones are typically algae eaters, but in addition to being used in tanks with fish to control algae they make a very interesting tank when limited to all shrimps. These shrimps come in different colors including a blue, a red and a zebra pattern. There are also what are called “bamboo” or “flower” shrimps, that get larger than the algae eating shrimps; these shrimps have their front 4 feet adapted into “fans” that filter fine foods from the water.

Crayfish – these guys make very interesting pets, and they really do best in a tank by themselves. Actually, they will do fine in a tank with fish, but some of the slower fish will end up being a snack for the crayfish. Crayfish come in a variety of colors, the most popular being a really nice blue, and they are easy to care for in a tank of their own.
All of these inverts – frogs, shrimps and crayfish – do really well in any of the small packaged aquarium sets that include the tank, filter and hood as one nicely integrated system. They do not require much space at all, and the smallest of these packaged systems are fine for any of these animals. They can usually do well without a heater, eat anything, and provide many hours of interesting watching.