Setting up a basic saltwater aquarium is much more expensive than setting up a basic freshwater aquarium, and this means that it is typically the dedicated aquarist with years of freshwater experience that decides to spend the necessary money on a saltwater aquarium.

The film "Finding Nemo" did however cause a saltwater boom, since a lot of people who saw the film wanted to keep a "Nemo fish", i.e. a marine clownfish. Unfortunately, a lot of clownfishes ended up in the hands of unsuitable keepers that weren't prepared to spend enough time, effort and money on their new pet.

If you are a comparatively inexperienced aquarist, you can still become a highly successful saltwater aquarist if you are prepared to spend a lot of time and energy on learning how a saltwater aquarium really works. Investing in suitable equipment and choosing some of the hardiest saltwater species will also greatly increase your chance of success. Do not hesitate to contact a saltwater aquarium club or a saltwater aquarium forum online and ask for advice and guidelines. Most saltwater aquarists are happy to share their knowledge with new aspiring saltwater aquarists.

One of the reasons why saltwater aquariums are more difficult to maintain than freshwater aquariums is that marine species tend to be much less tolerant to organic waste products and other forms of pollution. The enormous water mass that constitutes the ocean will rapidly dilute organic waste down to very low levels. Marine creatures are therefore not used to high levels of soluble waste and do not know how to cope. There are of course many freshwater species to be found that are also highly sensitive to organic waste and very difficult to keep in aquariums.

Generally speaking, it is however much easier to find sturdy freshwater species since freshwater fish can live in small lakes and even puddles where the levels of organic waste can reach very high levels.

Compared to marine species, these fishes will also typically be more suited to cope with all forms of change. In a smaller body of water, the temperature can for instance shift rapidly. Water hardiness and pH can also be affected by external factors.

Trying to keep the environment in a freshwater aquarium as stable as possible is therefore good training if you plan on setting up a saltwater aquarium in the future.

The overall chemistry and ecology are also different in a saltwater aquarium, since the presence of salt affects chemical as well as biological processes.

This is however not only a problem, it is also a possibility. You will for instance be able to use a protein skimmer in a saltwater aquarium; a very powerful form of filtration that will remove tiny organic waste particles before they begin to decompose.