I set up a small freshwater tropical tank, its only a few weeks old. I had a guppy (fan-tail) and a neon tetra. I added a silver - tipped tetra last tuesday. Yesterday and today, the guppy has been endlessly chased and nipped by the silver tipped tetra. The guppy looks very stressed. It has something wrong with its eye too, you cant see the black part very much at all on one side, and I'm pretty sure that it wasn't always like that and that it has only happened in the past day or two. Could it be injured by the silver tipped tetra, or is it more likely to be something else? Should I try and post some photos? Although I'm struggling to get a very good look at it.