The gemara in Chulin (63a) says that when Rebbi Yochanan saw a Shalach (a non Kosher bird) he would say the pasuk "Mishpatecha Tihom Rabba", your judgement is like a deep abyss (Tehilim 36:7). Rashi says that the Shalach is a bird that flies over the water and swoops down to prey on a fish, which it plucks from the water. This, says Rashi, shows that Hashem takes revenge on those who deserve to die. What is the significance of this particular act of preying that depicts Hashem's revenge?
Maybe we can conjecture that the fish that the Shalach eats is a predator himself. Yet he knows that in his turf in the ocean no one can exact revenge on him. He is the king of his turf and is protected in his environment. Hashem teaches him a lesson, that although in his eyes the world is limited to his underwater habitat, in reality there is a much bigger picture. There is a world above his cloistered confines. And from that world, from the Heavens above, Hashem can send an angel in the form of a Shalach to swoop down and take revenge, even in his deep water abyss.
We often look around and think that the cards are stacked in our favor and we are protected from Hashem's judgement. But it is not so. Our picture is limited to the confines of our mind. Hashem's world is far beyond our naive outlook. From the Heaven's, Hashem can come down and strike us and we wouldn't even know what hit us.
On the flip side look at it from the small fish perspective. We must realize that even if we are being hunted by a far larger fish and it seems there is no help in sight and we are doomed, there is far more to consider than meets the eye. Even when we think we are trapped and the bigger fish are closing in on us, a Yeshua can come from places far beyond our imagination. Hashem's means are vast. Never lose faith!