This is meant as a general care guideline for fish. There are many different species of fish and the needs of one may differ from those of another, so be sure to discuss specific questions with a knowledgeable veterinarian familiar with aquatic animals. Be sure to research the needs of the species of fish you are adopting. Habitat: Depending on the type of fish you choose, you’ll need an aquarium large enough to support the fish’s growth, with an air pump and submersible heater. A good rule of thumb for aquarium size is one gallon of water per every inch of full-grown fish. Tropical fish require heating elements in their habitats, but there are some freshwater fish (like goldfish) that prefer cooler temperatures and may not need a heater. It’s crucial that you do your research to find out what specific equipment the pet fish you’re considering needs. Diet: Fish don’t have stomachs, so they never know when to stop eating. When feeding your fish, only feed it as much as it will eat in two or three minutes once or twice per day. Overfeeding is one of the most common mistakes fish owners make. Fish foods usually come in flake form, as pellets, or freeze dried. Special treats, like bloodworms and brine shrimp, can also be purchased from pet stores freeze dried and frozen. Feeding your fish freeze-dried food is preferred over live fish as it removes the risk of disease transmission. Make sure the food you purchase is appropriate for your fish species.Other care: Aquariums require regular water changes and pH testing to ensure fish are living in proper conditions. This can depend on how many fish you have in the aquarium and the type of fish. https://www.petmd.com/fish/care/evr_fi_how-to-care-of-fish