Lastly try to avoid overcrowding the tank. This is another common problem that can be easily avoided. A general rule of thumb is one small fish per every ten gallons of water. Keep in mind however, that what is considered a small fish, may not be so small next month. Research, again is important because it is necessary to find out how large a fish will grow and weather or not it is compatible with its tank mates. Freshwater fish are usually hardier than marine species and therefore a little more forgiving when it comes to water acclimation. It is recommended that only experienced fish keepers with a real commitment to the hobby attempt a coral reef aquarium. A tank containing coral reef life may require several months of cycling before getting the water just right. Reef aquariums can be tricky to maintain and must be thoroughly researched before attempted. The last category of saltwater aquariums is the specialty aquarium. An example of a specialty aquarium would be an aquarium full of sea horses. Sea horses should not be kept with any other type of fish or marine life, because they are timid and slow eaters. Caring for Bubble Coral in an Aquarium As more and more people set up saltwater aquariums, more are also adding coral to the d cor. As with any living thing, it is best to understand the creature and how to care for it properly before bringing it home. Coral is no different as it is a live animal that you will be adding to your tank. Live plants may be kept in aquariums alone or with fish. The plants may even be used as a food source for some species of omnivorous fish. At the very least, they will provide shelter and a feeling of refuge for the fish. All plants require some form of light in order to thrive through photosynthesis. Check with the supplier before purchasing and be sure that you are willing to make the commitment to have food delivered if necessary. There are two different types of invertebrates, tropical and cold water. Make sure that the type you are buy is compatible with its other tank mates. A few examples of tropical invertebrates are tubeworms, red hermit crabs, cleaner shrimp and the sea apple.