The mayfly swarm came inland enough that both the gas station and carryout near my house were covered with 'em.

I got inspired and grabbed a lidded bucket and my biggest net and went out to catch me some to feed my natives. Rather than go to the busy gas station, I went to the already-closed-for-the-evening carryout.  I did think ahead to park parallel to the building, so as to minimize the viewf rom the street of my bug-catching endeavors.  I got a BUNCH of 'em in short order.

I hadn't really thought through just how I was going to get them from bucket to tank without winding up with some flying around the room. This wasn't a huge hit with my bug-a-phobic housemate.  I wasn't popular there for a few minutes.

I figured it out though, and managed to get the majority of them from bucket to tank.  What surprised me was that the sunfish didn't snap them up.  They stayed lower in the tank.  The shiners went to TOWN though, gobbling up everyghing, even the wings.

So, anyhow, now you know of at least one use for the things if they are swarming your house.

My oscar went nuts over them.  When the furnace in the house died when I was on vacation one spring his tank got down into the 50's.  He did not eat for almost two months until I tried feeding him mayflies. He went nuts over them for two weeks and was back to normal after that.