With hundreds of varieties of tropical fish to choose from, the beginner may be tempted to buy too many fish or become fascinated by some rare and exotic fish, hoping to feature it in the aquarium. The reason some tropical fish are rare and expensive is that they are extremely difficult to rear. These should be left to the expert, for in inexperienced hands they are a waste of money and the fish suffer needlessly.
There are two main groups of "easy to keep" tropical fish; the egg-layers and the live-bearers ie. fish which give birth to live young.
Some specialist aquarists have several different tanks, one tank of community fish ie. varieties which live peacefully together. Not all tropical fish make good community fish, as some of them are bullies and damage or kill smaller fish.
Start stocking your tank with egg-layers. Buy a few carefully selected pairs or several pairs of one variety, add more later, and then add some suitable live-bearers after the egg-layers are fully established
Select several varieties of tropical fish which generally swim in different areas of the tank, so that you get an overall colour picture rather than a crowded patch and empty spaces. For example. Zebras and other Danios, among the egg-layers, keep mainly to the top of the tank, and Tetras usually swim in the bottom third of the aquarium. Live-bearers swim as they please anywhere in the tank, and a couple of Catfish will complete the picture as they keep to the bottom gravel area.
Tropical fish are not as greedy as goldfish, but they need to eat more frequently as they live in warmer water and they should be fed three to five times daily with minute quantities of varied foods. As they mature, two to three meals will suffice, although there is no harm in keeping up the frequency of feeding. (I feed my fish every time I pass the aquarium if they are interested).
Just pouring food into the tank and leaving the fish to "get on with it" can only lead to rapid overeating, causing constipation in the fish, and to pollution of the water by waste food.
This is simply a first step guide only.