Fish can and do get the bends, at least in one particular case I heard about. This happens around large hydroelectric dams where the water really gets churned up. The water mixing with the air will pick up nitrogen. It's nitrogen that is the culprit for the bends. If enough nitrogen gets picked up (nitrogen supersaturation it's called) then the fish will take it in through their gills. Like in humans, nitrogen bubbles will build up in bloodstream of fish to the point where the fish gets crippled.

I think some clarification is needed here. Humans get the so called "bends" when they are diving in water and ascend back to the surface too quickly. At the air/water surface the pressure is less than when a person is deep under the water. If one spends enough time at a deep enough depth, more gases will be forced into the blood. If one returns quickly to the surface, these gases will be released out of the blood too quickly and form actual gas bubbles in the blood vessels. When these air bubbles form and block the flow of blood an air embolism occurs. This is the bends. Think of how all the bubbles form when you open a soda bottle. So, can an air embolism occur in a fish? I don't know. Obviously if this occcured allot we'd have a bunch of dead fish. I think fish naturally change depth gradually and therfore do not experience the bends. Or they have a physiological mechanism that aides them in avoiding an air embolism. I know when deep biological samples are collected, they must be kept at pressure or they simply blow up by the time they reach the surface. I think the previous answer is getting two conditions mixed up. Nitrogen narcosis is another condition where under increased pressure, nitrogen replaces oxygen in our blood and therefore there is a decreased availability of oxygen. This reduced oxygen level causes divers to act as they are drunk. The deeper a diver goes the greater the effect. This is assuming a standard air mixture is being breathed. Nitrogen replaces Oxygen in the bloodstream and therefore sufficient oxygen requirements in the brain are cut off. Thus the drunken stupor effect of Nitrogen Narcosis.