Watching how a trout puts on the brakes is always interesting to me, especially since it’s not something that’s easy to observe in the moment. (In many waters we never get the chance, period.) The fish in this picture has just come to an abrupt stop in order to inspect and inhale a nymph. As you’d expect, his pectoral and ventral fins flare symmetrically to their respective sides. But the relation between the remaining fins is what I find most striking. Despite none of them having a natural pair, they still function together. Here, you can see the fish flares its caudal and dorsal fins hard to the left. Anal and adipose flare to the right, working together with—but in opposition to—the caudal and dorsal fins. This balanced fin action allows the fish to come to a quick, complete stop while maintaining its direction and attitude in the water. Pretty cool to see, I think.
- John Juracek
- Sep 05, 2020