yes, well there are certian things you can by to make the water (for fish only) healthy, im sorry, but i dont have the bottle any more and i dont remember the name, but if you go to a pet shop or SOME vets and tell them they will know what you are talking about. angel fish are tropical and have cartain food and water needs, all tropical fish need a heater in their tank (NOT a normal heater, you will find them at you local pet shop) - unless your having them for dinner ;) .the chinese fish are great because they are also known as the Algae Eater so they eat all algae that grows in the tank, they are also very strong fish and make great pets, but they are also Freshwater Fish witch means they need different water types then the angel fish. your angel fish could have lived up to 20 years old if looked after well, so dont worry, they didn't sell you an old fish, and the chinese fish can live up to 8 years.
good luck, Elizabeth