I'm a bit concerned about one of my guppies. His tail fin is ripped and giggly missing. All the others are fine and he's swimming about in his group and eating well. I've just noticed one of my silver dollars has a slightly ripped tail fin but is ok too. Do you think he's ok. I wondered if he has been picked on but he is still in his little school of four guppies. None of my other fish have the problem. Any answers would be greatly appreciated.