When considering the weight of a living insect, it’s best to consider its density. The question should not be asked how much a fly weighs in grams. Rather, we should ask how much density an insect has at any given point in time. If you’ve ever driven a motorbike, you’ll be familiar with the question of the density of an insect at speed.
Weight is important to fly fishing, especially when choosing a fly line. Your fly line should be heavy enough to cast a fly correctly, and the weight of the line should match the weight of the fly. The size of your fly depends on the type of fish you’re targeting. Generally, the line you use should weigh about five to eight grams.
Brass is the second lightest metal you can use when fishing. It has a density of 8.70 grams/cm3. Despite its weight, brass is best tied into beadheads or coneheads, adding a bit of flash and slow sinking. However, when using brass beadheads, you should always tie an extra weight below it.