Why is my goldfish sitting at the bottom of the bowl?

Only five hours ago I bought a goldfish from a pet store. They advised me that it would be best if I got a tank with a filter but as I only wanted the one fish a bowl should be fine as long as I clean it regularly. I went ahead with this as my aunt has now had her fish for 20 years and it has always just been in a bowl. It's not sick already is it? It's not swimming at all.

Maybe because it's hard for your fish to breath. Filters help clean tanks & removes toxic buildup of ammonia and narrates. But I honestly doubt that's that case, I don't think you NEED a filter as long as you clean the tank regularly, you could've got a 'faulty' fish when you bought him :( hope I could help

Your fish is probably in shock, add some aquarium salt to the tank to add electrolytes. Also goldfish should not be kept in bowls, a goldfish should have heavy filtration, and cold water. A good rule of thumb is twenty gallons per goldfish. Plz, goldfish r great petz just house them properly, if u want a "bowl" fish get a betta!