Caring for saltwater fish includes having the right equipment, proper fish nutrition, and maintaining healthy water. Equipment includes the basics: a tank, filtration system, and a light source. Fish nutrition depends on the type of fish you have, but most saltwater fish have fairly simple nutritional needs. Proper water conditioning is vital for a successful saltwater aquarium.
You can choose either a glass or acrylic tank when caring for saltwater fish. Acrylic tanks come in more varieties of shapes than glass tanks, and are better insulators. An acrylic tank is also clearer, and allows in more light, than a glass tank. However, acrylic tanks are far more expensive than glass tanks, often two to three times the price. Acrylic is also very easily scratched, and you must be very careful when cleaning both the inside and outside of the tank. Tank size is an important consideration, especially when caring for saltwater fish. Larger aquariums are often easier to maintain, particularly with saltwater tanks. Because the water must be properly treated for the fish and plants to survive, having more water allows you a wider margin of error and a more forgiving environment.
Your filter system may be biological, mechanical, or chemical, or could employ a combination of these types. The most common filtration system for saltwater aquariums is an under gravel biological filter. Water is pulled either down through the gravel or (with a reverse flow filter) down from the top of the tank and then up through the gravel. The size of the filter you need when caring for saltwater fish will depend on the capacity of your tank.
When caring for saltwater fish in a tank with no live rocks, a full-spectrum fluorescent light is fine. If you have live rocks, fluorescent and actinic (blue) lights are better. Select a heater appropriate for the size of the tank, and invest in a quality thermometer to monitor the temperature. The correct temperature for the tank will depend on the fish living in it.
Fish nutrition is an important part of caring for saltwater fish. Fish food comes in a variety of forms. Common types include flakes, pellets, frozen food, and gelatin. Different fish require different foods, and may need to be fed on a different schedule. Always find out the individual nutrition needs of particular fish before adding them to your aquarium. Since you cannot generally segregate fish during feeding time, or keep most of them from eating whatever is put into the tank, it is important to keep species with similar fish nutrition needs.
Caring for saltwater fish includes making sure the water is safe for them. To ensure proper water quality, use a water conditioner to remove chlorine from the 
water. When setting up your saltwater aquarium, mix the salt and water to a specific gravity between 1.020 and 1.025. You also need to keep the water clean. Cleaning your aquarium is something of a balancing act. You need to remove the “bad” dirt while still keeping plenty of the helpful bacteria that have built up in the tank. You also need to be sure to keep your fish safe and calm during the cleaning process.
Caring for saltwater fish has many important components. While none of these are very difficult, it takes planning and some research. Having the right equipment and information makes caring for your saltwater fish fun and rewarding.
