White spot is arguably the most common disease that tropical fish are subject to, and is believed to be responsible for causing more fatalities than any other disease. Most - if not all - aquarists will encounter white spot (also known as Ich) at least once or twice during the course of their career/hobby.

But what about the actual fish? How do you choose which ones you want? How do you know whether they'll be too big for the tank when they grow up, or whether they'll be compatible with your other fish? How do you find out how to stock your tank?

However, when levels get high enough to be visible to the naked eye, you've got a surplus.Unless you maintain your aquarium regularly, you can pretty much count on regular growths of algae obscuring your fish, making the water smell, and generally detracting from the aesthetic appeal of your tank.

This is because freshwater fish are much easier to look after, and are generally more resilient to less-than-perfect water quality and fluctuations in temperature (and, really, all the sorts of mistakes that beginners are prone to make!). In general, freshwater tanks are both cheaper and easier to maintain than saltwater ones.

After approximately one week of parasitism, the now-mature organism (mature Ich cells are called trophozoites) detaches from the fish and settles on a new surface: usually, a plant or ornament.

Unfortunately, choosing fish for an aquarium isn't as simple as you might think. You can't just go into a pet store and select arbitrary numbers of the fish that you find the most appealing - you need to invest some forethought into your tank to ensure that your fish lead happy, healthy lives.

These "daughter cells" will then break loose and swim freely about the tank, attaching themselves to new fish - and beginning the cycle all over again. White spot is highly contagious and progresses very rapidly. 100% mortality is to be expected unless something is done about it.

Compatibility. Contrary to popular belief, fish do actually have personalities - and some of them can get pretty aggressive. Many tropical fish have well-deserved reputations as bullies: they can nip the fins of other, more peace-loving fish, they can 'barge' smaller fish, and they can get into fights (which are frequently pretty vicious). To eliminate the likelihood of your fish getting into scraps, you should aim to buy fish that have mutually compatible