It is recommended to keep a variety of plants in the aquarium for guppies to seek refuge. There should be about one to two inches of substrate in the bottom of the tank. Colored rock or dead crushed coral make a nice addition to the aquarium, and may help to make the fish feel more at home. A few varieties of guppies are the Fantail, Flagtail, Spadetail, Deltatail and the Roundtail. Only in combination with some larger Cichlids can there be a problem as the Cichlids tend to extend their territorial claim to the entire tank. The one thing to consider before adding a catfish to your existing aquarium set-up is the size of the other fish. While catfish generally get along with most fish, they are a predator and will attack and feed on smaller fish. This may seem silly, but the main cause of sickness in fish is stress. So, a happy fish is a healthy fish. Check to see that all lights and filters on the aquarium are plugged in and functioning correctly. Feed the fish daily. Only feed what can be consumed in the first two to five minutes. Any excess food will become debris in the tank and lead to illness or attribute to excess nitrite levels. It is imperative to keep the salinity levels, P.H. and temperature consistent in a saltwater aquarium. Test the water daily and make any necessary adjustments immediately. Check the water for cloudiness and clean the filter regularly. Have you ever heard the saying that a happy baby is a healthy baby? Follow through with the set up as you would a freshwater tank. When you are ready to add the water to the tank, follow these simple steps. First, pour the sand into the bottom of the tank. Add dechlorinated water to the tank. Next, add the salt and make sure it is mixed until the specific gravity measures 1.205. Try to remove any loose or floating debris at this time. When adding the new water to the aquarium, be sure that it is within approximately two degrees of the tank water. The sides of the aquarium should be scrubbed regularly to remove an algae build up. Again be careful not to disturb the fish. Wash your hands thoroughly before and after handling the aquarium.