how to know if male or female fish?

Hello there, just want to share with you some ideas about sexing of certain fishes. For swordtails, males have long swordlike located beneath its body. Male swordtails exhibit more vibrant color usually from bright red-orange to bright orange while female swordtails are paler in color. For the common goldfish, it is quite difficult to determine since its body are always rounded and usually the petshop owners aren't informative and updated to the nature of the fishes they sell. My advise is do a lot of searching when you like a certain fish before you purchase it so that you have an idea how hardy or fit a certain fish would survive in your aquarium tank. Based on my experiences, it's a trial and error process what fishes would be suitable for your aquarium setup. Check what type of water in your local area whether it is hard or slighly acid since certain type of fish like goldfish like hard water. Swordtails prefer slightly alkaline water to breed successfully. For beginners, I recommend the following fishes: common goldfish, black tetras, mollies, platys, gouramis and certain angelfish. If you like minimal maintenance and simple setup, beta splendens or commonly known as "fighting fish", would be a good choice. It needs no air pump or filter. A small, square tank glass would suffice for a single fighting fish. Male fighting fish is distinguished by its vibrant colors of red, blue, violet,etc. Female variety is dull and pale in color. Hope this advice and suggestions would help you a lot. Happy fishing.