There are several types. The most common is coldwater fish, known as goldfish, freshwater tropical fish are also popular with lots of variety to choose from. Marine or saltwater fish are the most impressive, when looking at colours:

• Marine – Saltwater fish & corals, are beautiful to keep but can be a little more expensive and the maintenance levels are a little higher. A heater and saltwater is needed at a minimum.
• Coldwater – Primarily goldfish, these types are a good starting point and relatively easy to keep.
• Freshwater Tropical – All need a heater with a temperature of at least 25c. There are a few groups in this section. They include:
  1. Community Tropical fish – Which are generally peaceful and easy to keep.
  2. African Cichlids – Bright colourful fish, can be aggressive and many different sizes.
  3. South American Cichlids – Beautiful fish, again some can grow quite large and be aggressive.
  4. Odd bods - Various types which have an interesting appearance or are just unusual.

Be aware that different species of fish occupy different levels of water. If you already have bottom dwellers like catfish, you might want a top dweller or mid-level swimmer instead. Species also have specific temperaments, aggressive or peaceful, and are either nocturnal or diurnal. Use the chart below as a guide on how many fish you may be able to keep.

Remember fish will grow, a fish 2cm today may become 5cm in 12 months or you could get a big shock when it's 25cm long and all your others have disappeared. So choose wisely and ask advice when in stores.

= Total length of fish in centimetres