My first fish were guppies, eight of them in a 3/4 gallon jar, water changed once a week, no filter, the whole lot lived about 2 years. I was amazed then. I still am.
My first 'real' tank I went on the advice of an LFS, 5 gallon planted stocked with 9 platies and a bristlenose. Fortunately I got flamed on a few forums (including this one) before I killed anything, realised my mistake and bought some more tanks. My parents still cannot believe their stupidity in allowing me a fish tank. I now have seven, not counting betta tanks.