The "Golden Wonder" is a golden colour morph of the Panchax Aplocheilus lineatus. I have never had the gold ones, but the originals I have had many times. These are a sparkly greenish fish with numerous more or less distinct vertical stripes.
They are peaceful enough with anything they can't fit into their quite large mouth. Guppies for example, will be eaten. Otherwise, they are easy to keep, easy to feed and easy to breed. Live a good deal longer then the many other types, 3-4 years is by no means unusual.
If you've never kept killies before, you couldn't really have picked an better species to begin with.