Emerald Green, Corydoras/Brochis splendens (they're arguing over the genus again) has more rays in the dorsal fin with the first spine longer than the rest of the fin. @Sarah73 , your photos are all Corydoras aeneus. The short, rounded dorsal fin makes this an easy ID. The splendens is also much greener, but the dorsal fin is the best way to differentiate the two. Many stores simply don't know the difference, or don't care.
Corydoras aeneus is a variable fish with a wide range in the wild. Also, there are populations sold as aeneus that are different species, or may be different species.
and @DaloAquatics , there is no such thing as a "Corydora". The word is Corydoras, whether singular or plural. It is the name of the Genus these fish belong to, so even one is a Corydoras. A common mistake, and one that I believe is often caused by auto-correct.