The dragon staying in the lake is big. It's twice the size of most dragons we fought back then and even the dragon in Luminous Continent is half of the size of the dragon we are seeing right now. If it was still being considered as a game, this is going to be a field boss or a Raid boss depending on how dangerous it was.
Based on its appearance alone, it is indeed similar to a poison wyrm the only difference between the two creatures is that the former is much smaller and looks more like a flying violet snake rather than a dragon and usually is missing hind legs.
As for this one in the lake, even if we are a distance away, I can clearly see the prominent features of the dragon. It's a huge jewel on its chest and forehead, four folded wings growing on its back, back sails that are very similar to a poisonous fish, and glowing violet color skin of the dragon that attracts the attention of anyone nearby.
