Mollies are one of the most recommended fish for beginners. They are extremely easy to look after and come in a variety of colors, including Dalmatian, black, green and orange, among others. It’s a good idea to only keep one gender of these livebearing fish, however, since they are prolific breeders and can rapidly overpopulate a tank. The adults will eat fry in the same tank.
These fish tend to grow to about 2-4 inches long, with males being long and slender and the females rounder. They prefer tall aquariums. They do not get along well with other species of fish, so it's generally best to keep only mollies in the tank. You can add just a little aquarium salt to the water to keep them healthy and thriving. About one teaspoon per five gallons of water is perfect.
Mollies enjoy a varied diet and will eat just about anything you offer them, from frozen, freeze dried and flaked food to live worms. They do best with a basic diet of flakes, supplemented with live and freeze-dried food.
For those just getting into saltwater aquariums, mollies are a great way to transition from fresh to salt, since they enjoy a little salt in the water, but are not particular if there is too much fresh water. They are also ideal for anyone who wants a simple species to look after; since they come in so many colors you can easily populate a tank with a variety of fish and enjoy the various designs and hues, without worrying about several different species.