Damsel fish are tropical, saltwater fish. Damsel fish are very easy to care for making them a great tank mate for the beginning aquarist. They are usually bright colors. They can withstand a variety of different conditions making. They are also very disease resistant. Most Damsels stay on the small size even as adults. Making them very suitable for a small starter tank. A single fish can be kept in a small 10-gallon tank quite well. The Blue Devil Fish belongs to the family of the Damsel fish, and very typically seen. Most Damsels are schooling fish, but it is a good idea to research the specific species you are looking at as there are many. Some Damsels should be housed alone unless you have a large tank with plenty of hiding places. These fish are very territorial. Coral provides excellent hiding places for these fish. Damsels are very aggressive. Damsel fish will eat pretty much anything given to them. They will nibble on algae as it accumulates in the tank. Damsels are not picky eaters. They accept a wide range of food. Damsels are omnivores. A well varied and balanced diet is recommended. Most Damsel fish are reef fish. They do well with any invertebrate you choose to add to your tank.