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.

Once you have your aquarium completely set up with or without a heater, you can decide on the fish to put in it. There are many different tropical fish available in the market. Although they need a heater, they are often more colorful than cold water fish.

A fresh water tank is easier for beginners than a salt water or marine tank. Fresh water fish are easier to manage than the marine species. For the beginner, any of the popular fresh water live-bearing fish, especially guppies, mollies, and so on or gold fish, angel fish etc will be the best. If one needs some fish more colourful, white cloud mountain fish is another option. All of these fish are fairly hardy, and can live at room temperatures. But most of the ornamental variety of freshwater fish are tropical, which require a heater.

Most of the marine fish species are tropical. Among the Marine aquarium fish species, damsel fish, clown fish (anemone fish) etc are best for beginners where as dragonets and lionfish should be kept only by experienced breeders with large tanks. Sharks, rays, batfishes etc should be avoided. Many marine species will be completely incompatible and necessitate careful selection of species when choosing which fish to keep in ones aquarium.

Things to remember before buying fish for your Aquarium

Once you have decided on a particular species of fish (either Fresh water or Marine) to keep, the next thing is to pick out healthy ones from the lot for sale. It is always better to avoid buying from a store which smells like fish as there may be dead or dying fish around. Avoid fish with cloudy eyes, faded or dull, with open sores and spots on their body. Avoid buying fish that are sluggish or appear to be shivering or the ones that are floating belly up. Take a good look at all the fish in a particular tank. If any appear sick, don't buy any fish from that tank. Choose an active, alert fish. Make sure the fish you choose will be compatible with each other. Characteristics of certain species also matters. Some fish are social but some others will kill each other. If you would like to keep some aggressive variety, be sure to keep them by themselves. Try to get fish pretty much the same size. When you purchase new fish it is better to keep them away from the others a few days to monitor them for diseases.