Deciding on keeping fish is the easy part, but deciding on what kind of fish to get, from the numerous species available is difficult. Reading all you can about the varieties of aquarium fish and their characteristics and all about setting up an aquarium helps a lot in making the right purchase.
It is always better to get an aquarium ready before buying fish as the fish needs to have a ready environment to live as soon as we bring them home.
The biggest consideration when setting up your aquarium is to decide whether you want to house tropical fish or cold-water fish. Both Fresh water and Marine species can be either Tropical or cold water i.e they may need either warm or cold temperatures to live.
Some fish are very hardy and relatively easy to keep, while others are so fragile that a temperature drop of a few degrees will kill them.
Choose fish for your tank that are fairly hardy and that require the same environmental conditions.
Some fish may not be compatible when put together. So you must make sure the fish that you choose for your tank are all compatible with each other.