The stretch nailfin split from it's ancestor and moved to warmer waters. They have doubled in size and have turned a lighter shade of blue to blend in. They have become much more stream-lined to move swiftly in search of food. They have lost the need for long nails, so now only the females have them, which they use to interact with their young. They have grown large teeth to dig up plants and to take down prey.
The males are solitary creatures that only socialize to mate. They now no longer have a specific mating season, but instead just breed when the female is in heat, which is every 3 months. The males use their long teeth to fight for mates.