I went to buy some new fish today, so I looked in my tank to see what I needed. I knew there were a couple that needed more added to their groups. I had my mental list: serpae, black skirt and blind cave fish. Off I happily went to the store.... Later in the day.... I was looking at the new cute little fishies and watching them find the others of the same kind and noticed something. The two bigger serpae were actually pristella. I have been keeping fish for over twenty years and have also worked with them for years, I KNOW the difference, so hence the title of this thread, what was I thinking???? I have three pristella, so if I thought the two bigger ones were serpae, did I not think I needed more pristella? I bought all the pristella at once and two are more than twice the size of the other one, but still, they look the same. Seriously, was I just so excited about buying new fish? At least my little serpae are cute....