First of all, not all winged ant-looking critters are ants. Some are termites. The difference between ants and termites is simple: ants have three sections to their body--head, thorax, and abdomen. A termite has only a head and a body.
Ants come in a variety of sizes and colors including brown, red, and black. Not all ants fly; usually the females have wings. The reason is that the female winged ant sometimes flies off from the colony to start another colony because they want to become queen.
Ants become important fish food when they swarm, fly, and then fall to the water’s surface. All fish love ants because they are almost pure protein…a great lunch. Ants will normally fly right after a heavy rain that brings them out of their nest. If they are mature enough to have wings, they fly and swarm. Sometimes during the swarm they also mate. During the mate, all male ants die which creates a food source for fish.
I like big ant patterns, mainly so I can see the fly. It’s popular to put a little hi-vis or other wing material on the back so you can track the fly. It’s also popular to use rubber legs to give it life on the water. Lots of ants are in the film of the water, as they don’t float well. If you see swirls during an ant swarm, trim down your floatation and fish in the film. Trout come to ants without hesitation. Generally there is little need for ultra delicate presentations or fine tippet material.