The Black Ghost Knifefish

“Behold, the Lord’s hand is not shortened, that it cannot save; nor His ear heavy, that it cannot hear.” [Isaiah 59:1]

The black ghost knifefish found in the Amazon Basin in Peru is a very strange-looking creature. It has no fins on the side, top, or tail. Its only fin is beneath in one long, single wave from front to back! This eight-inch fish has no tail and looks somewhat like a sideways butter knife, which narrows to a dull spear point at its back end. The one long, ribbon-like fin undulates from one end to the other. It looks something like a graceful, rippling black curtain that moves it through the water.

The knifefish has small, beady eyes and poor eyesight, but God has given this odd creature another way to see. The most unusual feature of the knifefish is its lateral line. This horizontal line of cells on its side is an electrical generating plant, producing waves of high-frequency impulses that are sent out into the water to both one side and the other. These impulses bounce off objects and quickly return, where they are sensed by other receptor cells in its skin. You might say this fish has a type of radar! The voltage of these cells is low, only about 3 to 10 volts of direct current. Yet the frequency of the impulses is high, running around 300 per second. As these impulses go outward, they create an electrical sending/receiving field of signals, which tell the fish what is all around it.

But imagine the problems that might occur when two knifefish come near each other! Both fish are sending out signals, and one might think the incoming static of confusing patterns would jam their signals, “blinding” both fish. But the Creator gave these amazing fish the ability to change wavelengths. As soon as two knifefish draw near to one another, they immediately stop transmitting impulses for a couple moments, and then both fish switch them back on, but this time tuned to different frequencies from the other.

Have you ever been praying and felt that you were on the wrong frequency? Maybe you were having a lot of background noise and static, making it difficult to concentrate. Such “noise” does not need to be sounds we hear with our ears. Static can come in the form of our thoughts as well. When we fill our minds with Bible truth, seeking to remove all the distractions of the world, we will be more tuned into the voice of God in our thoughts (Isaiah 30:21).