Why Do Deep Sea Fish Explode When Brought To The Surface

Why Do Deep Sea Fish Explode When Brought To The Surface

Imagine reeling in a weird-looking creature from thousands of feet below the ocean surface. As it gets closer to the top, its eyes bulge, its stomach pushes out, and its body swells up like a balloon before bursting apart right before your eyes.

This gruesome exploding fish phenomenon happens because of the huge change in pressure between the deep sea and the surface. Let’s look at why this happens and how we can prevent deep sea fish from exploding.

See also: Can you eat deep sea fish?

Why Deep Sea Fish Can Burst at the Surface

Deep sea fish live under immense pressure in the deep ocean, which can be up to 1,000 times greater than surface pressure.

To put it into perspective, the pressure at that depth is equivalent to a large elephant standing on your thumb.

This high pressure is needed to counteract the buoyancy of gases and fluids in their bodies so they can maintain neutral buoyancy.

When deep sea fish are brought to the surface too quickly, the rapid drop in pressure causes gases and fluids in their bodies to rapidly expand. This can cause deep sea fish to rupture or even appear to explode on the surface.

Pressure Differences

DepthPressureTimes Greater than Surface Pressure
Surface1 atm1x
100 m5 atm5x
500 m15 atm15x
1,000 m30 atm30x
3,000 m90 atm90x
6,000 m180 atm180x

The Swim Bladder

The main cause of exploding or rupturing is expansion of the swim bladder. The swim bladder is a gas-filled organ that many deep sea fish use to control buoyancy. Under high pressure, gases in the swim bladder are compressed.

When pressure drops at the surface, these compressed gases rapidly expand, which can cause the swim bladder to burst. This rupturing of the swim bladder is called barotrauma.

Other Factors

Other organs and tissues can also be affected by the huge pressure change:

  • Eyes – The pressure drop can cause eyes to bulge and rupture.
  • Stomach – contents can expand and be forced out.
  • Heart – Can fail due to pressure changes.
  • Tissues – Expanding gases and fluids can rupture throughout the body.

This expansion of gases and fluids makes it appear like the fish’s body explodes.

Decompression Times

DepthTime Needed for Safe Decompression
100 m30-60 minutes
500 m2-3 hours
1,000 m5-8 hours
3,000 m48-72 hours

Proper Decompression Needed for Survival

To avoid barotrauma and increase survival, deep sea fish need to be slowly decompressed when being brought to the surface.

Special pressurized tanks are used to gradually adjust the pressure and give deep sea fish time to adapt safely. This prevents over-expansion of gases and fluids in their bodies.

Fish Without Swim Bladders Less Prone to Exploding

Some deep sea fish species, like lanternfish and bristlemouths, don’t have a swim bladder. They are less prone to rupturing and exploding because they have less gas and buoyancy issues.

However, these fish still need proper decompression when brought to the surface, as they can still experience barotrauma in eyes, stomach, and other organs due to pressure changes. Gradual decompression helps their survival.


In summary, the huge pressure change causes gases and fluids in many deep sea fish to expand rapidly when brought to the surface, which can make them appear to explode. Proper decompression procedures are essential for their survival, unless of course you plan to eat them anyway!

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Steve Momot

Steve Momot

Steve is an accomplished professional photographer and marketer who specializes in the Fishing, Yacht, and Boating industry. With a strong presence as an influencer and marketing expert in the Marine Industry, he has made a significant impact in the field. Additionally, Steve is the original creator and co-founder of Sportfishtrader. Prior to his career as a marine photographer, he gained extensive experience as a licensed boat and car dealer in South Florida.

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