Roach certainly are not one of the biggest fish, but they are a lot of fun to catch. A roach of 2lb is a dream fish for many anglers, but they have been known to go up to 4lb in size. The good thing about roach is that they are a shoal fish. If you get them on a feeding frenzy you can certainly soon get a good netload. Usually, an average size roach would be around 6oz.