They look like "difficult" fish because they look so beautiful, but although they tend to be a little weak when they are young, when they get bigger they become stronger and turn out to be fabulous aquarium fish and they are even easy to breed. Angel Fish should live in a large aquarium of at least 30 gallons. The gravel should be at least 1/4 of an inch thick, and the temperature of the water needs to be kept between 78 and 82 degrees Fahrenheit with the use of an aquarium heater.
Angel Fish are part of the Cichlid family and if you only have two or three angels in a tank, the strongest one will attack the others, so it's better to have a single Angel, or have them in groups of six or more in a large tank of 50 gallons or more, with a minimum of 18” depth.
Many other fish that can live in the same tank with Angels. Silver Dollars, large Tetras, Swordtails, Platies and Mollies, Bala Sharks, Gouramis, Rainbows, Clown Loaches and Giant Danios... Just don't put smaller fish like neon tetras or Guppies with Angel Fish because they’ll become dinner!
There is a wide variety of Angels, like the Silver. This is the normal coloring of wild Angels.
But there's also: Zebra, Black Lace, Black, Half Black, Veiltail, Marble, Golden, Blushing and Pearl Scale.
Live foods such as Adult Brine Shrimp, Black Worms, Mosquito larvae, finely chopped earthworms and Guppy fry are happily accepted and you should include them in their diet regularly.
If live food is not available, you can get frozen packages of Blood Worms (Midge Fly larvae), Brine Shrimp and others.
An eventual hunger strike should not be a problem if you have a well maintained tank. As long as you do regular partial water changes and you follow the guidelines for cleanliness, this should never happen to you.
If you notice your Angels are not eating, bribe them with live brine shrimp, live guppy fry or any other clean live food. They'll start eating again in no time.
The typical aquarium life of an Angel Fish is about ten years, although with outstanding care they may live longer. They grow up to 6" in length, the top and bottom fins spanning a greater distance in the Veil varieties.