Mesmerizing, calming, and beautiful to look at, fish tanks can be a tranquil addition to any room. Saltwater aquariums are particularly stunning because they house some of the most vibrant and unusual aquatic life. Here, Justin Muir, owner and principal designer of City Aquarium, explains how to outfit a saltwater aquarium for the home.

Saltwater vs. Freshwater Tanks

Freshwater fish are found in rivers, streams, ponds, and lakes, and adapt to a wide range of aquatic conditions. Saltwater fish, on the other hand, are collected from oceans and seas and require a stable environment; they do not readily adapt to major changes in water chemistry or temperature.

Though saltwater tanks generally cost more to build than freshwater (due to the mechanical systems involved in keeping the water healthy), the fish display notably more color and personality and are requested by more than 90 percent of Justin's private clients. Saltwater tanks should be stocked with less fish than freshwater tanks; the rule of thumb is one inch of fish (measured from the nose to the base of the tail) per five gallons of saltwater. pH, nitrate, salinity, and temperature levels must be monitored and kept stable.

Preparing Saltwater

To make saltwater for an aquarium, pour freshwater into a bucket and add a capful of dechlorinator. Then, add salt slowly, using a salinity meter to make sure the amount of salt in the water is within your target range.

Selecting Fish

Saltwater fish fall within three different aquarium categories:

Species Tanks: Fish or animals that must be kept by themselves or with others of their own kind, either because they are delicate creatures or because they are too aggressive.

Community Tanks: Fish that generally are peaceful, not aggressive, and can readily be kept with others of their own kind or with other peaceful tank mates.

Aggressive or Predator Tanks: Fish that are highly aggressive or predators and should be kept only with other aggressive species of their own size.

Use fish compatibility charts such as those available on and to choose fish that will live well together.

Justin recommends purchasing fish and supplies at small, specialty shops or stores that cater to serious fish aficionados, as you will generally find a higher quality stock. To insure you are purchasing a healthy fish, study the fish's behavior and look closely at its body and features. You should not be able to see the fish's skeleton or bones; instead, the stomach should be plump or rounded, never pinched. The eyes should be clear, have no spots or white film, and be sharp and alert. The body should be free of white or colored spots or mucus. If the fish is swimming erratically, or scratching itself against a rock or the bottom of the tank, there is a good possibility it may be sick. As an extra precaution, ask someone who works at the pet store to feed the fish: A healthy fish will always eat; if the fish does not eat, do not buy it.


Saltwater fish seen on the show include Clown Trigger Fish, Golden Puffer Fish, and French Angel Fish. For more information, visit

Comments (2)

Martha Stewart Member
July 19, 2011
Forthefishies needs to get a clue about the hobby, So does the guy in the video. Living coral is better than this fake stuff he has in the tank. There are many fish that can be with "plants" in the aquarium. I am not sure who this guy is but I would not wanting in taking care of my tank. I also enjoy how he had fish that do not get along in that tank. I feel bad for them. Sad that this was on TV!!
Martha Stewart Member
April 15, 2011
The saltwater aquarium trade and hobby is a MAJOR threat to the world's reefs - per the U.S. coral reef task force. It treats coral reef wildlife in a cruel and inhumane manner - per the Humane Society of the U.S. Even Hawaii's populations of yellow tangs (the yellow fish depicted in your tank photo above) are down by 73% because commercial collecting for this hobby - per Hawaii's Div. of Aquatic Resources. Go to to learn more.