Will Pure Oxygen Gas Kill Live Bait and Tournament Fish?

WEBPAGE UPDATED                                         Wednesday  January 1, 2020
NO, of course not! Pure oxygen dissolved in livewell/bait tanks water will not kill, poison or injure live bait or tournament game fish during live transports. Continuous 100% DO Saturation with the livewell chock full of fish or live bait is ideal during live transports.

Yes, pure oxygen bubbles can kill live bait and game fish! Diffusers that make Micro-fine pure oxygen gas bubbles so small they make the livewell/bait tank water look water look milky or cloudy, so tiny they  remain suspended within the water column can be very toxic, deadly for captive live bait and tournament game fish. Beware of all diffusers capable of making those  micro-oxygen gas bubbles that remain suspended in livewell/bait tank water that cannot escape the water surface.

Live bait and tournament game fish exposed to concentrated Toxic Micro-Fine Oxygen Bubbles  in livewell and bait tank water during live transports can kill.

Diffusers That Make Those Toxic Micro-Fine Oxygen Bubbles in livewell water are a known precursor to gill damage, infection, tissue scaring, disease and death. Pure gaseous oxygen is corrosive. Gill tissue as well as corneas, scales and skin exposed to pure 100% oxygen gas bubbles can cause chemical  burns to delicate tissue. Pure oxygen is a very powerful oxidizing agent especially to organic tissue and cell membranes.

A familiar example of the oxidative power and use of oxygen is the use of hydrogen peroxide, H2O2.

Unlike oxygen dissolved in water, the oxidation process of oxygen atoms are incredibly reactive destroying delicate cell membranes when in direct contact with highly concentrated pure oxygen gas bubbles that literally stick to fish tissue.


1. Water and gas chemistry – micro-fine oxygen bubbles so tiny they remain suspended in the water column that make livewell water look milky transfer oxygen into solution fast and efficiently, quickly saturating/supersaturating water in seconds in a typical 20-30 gallon livewell or bait tank. Diffusers that make larger bubbles may take an extra minute or two to achieve the same DO saturation/supersaturation, but the final result is the same DO Saturation.

2. Fish Physiology and Fish Pathology – another matter that is seldom mentioned is that micro-fine oxygen bubbles negatively affect fish health – oxygen poisoning caused by continuous exposure to micro fine oxygen gas bubbles that coalesce to fish gills, cornea’s, scales, skin and fins can cause serious chemical burns and tissue damage resulting in blindness, death or disabling scar tissue if the fish survives the initial insult. Oxygen toxicity is usually caused by the fisherman’s ignorance of the device that makes the oxygen bubbles in his livewell water.

Micro-pore oxygen diffusers and livewell water pumps that entrain oxygen or air on the inlet side of a water pump’s impellers gas venturi device can produce thousands of suspended micro-fine gas bubbles in the livewell water column as the oxygen goes through the pump’s impellers. The size of an oxygen or air bubble can dramatically affect livewell water chemistry, gas transfer rates and dissolved gas concentrations.

We queried university professors and experts. Our concern is the pathophysiology (oxygen toxicity) occurring when micro-fine oxygen bubbles stick inside fish gills, get into blood, stick in eyes, on scales, fins and skin.

We asked University Professors, Fish Physiologist, the real fish doctors:

When captive fish are forced to breathe in clouds of suspended micro-fine oxygen bubbles (so fine the water looks milky) in livewells with relatively small functional water volumes, can these tiny gas bubbles injure fish or bait?

Is the stress response increased? Is the probability of delayed mortality increased?

Are we actually causing physiologic harm to tournament fish or live bait when holding and transporting them in clouds of bubbles for hours or even all day?

When we transport tournament bass, redfish, snook or live bait for hours or all day, what happens to gill tissue when thousands of tiny oxygen bubbles remain stuck in gills, on scales and fins all day?

Images and examples of these problems – see Ph.D. “Opinions” link.

We thank these university professors for offering their time,  providing their knowledge, expertise and opinions freely so that catch and release tournament anglers, as well as fishermen worldwide, can become better educated and hopefully take better care of live tournament fish and live bait in livewells and bait tanks during live transports.

We appreciate these expert opinions in fish cardiovascular physiology, fish biochemistry, fish pathology, fish physiology, and the principles and practices of modern aquaculture techniques.