I have a guppy and his tail fin ( Sorry not sure of technical name) has ripped and or torn down the middle. His tail fin is pretty much in half but it don't look like it's bothering him at all. He is swimming and eating like normal. I would get a picture of him but he is to fast to get a decent one.
I figured since he is acting normal that I should not worry but I just want to make sure. No other fish are bothering him at all he is completly normal. My guess is that he might of got it caught on something and it ended up ripping it but I just want to make sure.