Animal HBOT, Diving, Gas Laws, Gas Science, Hyperbaric Oxygen Therapy, Marine Biology, Physics, Science, Small animal HBOT

A story about a little fish – HBOT… Not just for the peoples

Emporor Chow Enjoying the Midwater

I trust this finds everyone safe and well during the lockdown and extended period of various isolation and distancing in which we now find ourselves. Good news from around the word is that HBOT is fast gaining momentum as a preferred treatment for COVID-19 with no fewer than a dozen ongoing trials and reported success from around the world of rapid recovery.

I haven’t written for a while because there literally has only been one thing in the public consciousness and there is a limited amount that can be said when it comes to the coronavirus and how HBOT solves the underlying hypoxemia regardless of the cause or pathology of that hypoxaemia. There is no benefit in banging on about it. The articles posted cover all the details. There are a multitude of articles including our own on the subject.

I digress, this was just a short hello from me with a story about a fish to lighten the mood, provide some homeschool physics and physiology for the younger audience and demonstrate that hyperbaric physics and physiology applies to all creatures great and small. From racehorses, which is a huge multi-million-dollar business, through cats and dogs to something as little as a Siamese Fighting Fish named Emperor Chow. Emperor Chow joined our family probably a year ago now. And all was well. He was first given a small bowl as is customary for a Siamese Fighter.

Thanks to my experience as a diving aquarist and years at the aquarium in Durban South Africa, I know them to be solitary creatures who are best housed alone. This led to the Emperor being given more salubrious accommodations in the form a small tank with pretty things. Following our house move, Chow unfortunately developed a swim bladder problem and began swimming only at the surface. Perhaps stress induced, it’s hard to know. This progressed to a distended and swollen abdomen and swimming on his/her side. (We aren’t really sure if Chow is a boy fish or a girl fish). At one point he/she just gave up moving around much at all and we feared the worst. Fortunately, I remembered a conversation I had with a colleague on the Isle of Man. We had spoken lightly of treating goldfish in hyperbaric chambers who were suffering from swim bladder problems.

As we know from Pascal’s Law, pressure transfers equally through a fluid. Air and water are both fluids so the pressure transfers through the water in the bowl where it can then act upon the air space. In fish, when the swim bladder fills with air or some other gaseous embolus and cannot be reabsorbed into the tissues or expelled in some way, they float… perpetually. They simply cannot swim below the surface. That is better explained by Archimedes Principal of buoyancy. Rather an unfortunate way to live I am sure you will agree. As we have learned in the article covering Boyles Law, when a gas is compressed its volume is proportionately decreased as pressure increases. A balloon in a chamber will be half its size at twice the pressure. The swim bladder is essentially an inflated balloon acting as a float.

By squashing the bubble Chow was immediately able to return to the bottom. We also learned from Henry’s Law that gas is absorbed in greater amounts by a liquid (in tissues) as pressure increases. So much like treating a diver for decompression sickness or arterial gas embolism, the bubble is squashed and then reabsorbed. This is the basis for treating decompression illness with hyperbaric compression.

Henry’s Law explains why gas remains in solution in the liquid whilst under pressure. release the presure an the gas fizzes out of soulution.
Pascal’s Law
Boyle’s Law explains the inverse and proprtional relationship between the volume and pressure of a gas.

As you all know, at Cumbria Hyperbaric we don’t have a chamber just yet. Fundraising continues. In this instance a repurposed soda bottle was fit for the job. Not many know that a pressurised soda bottle holds about 3 bars of pressure when it is sealed when you buy it. It can handle a little more too. Don’t try this at home though. The lid can make a rather unpleasant projectile if filled with only air. When filled with water its a lot safer to pressurise. Properly modified however I managed to fit a valve and fashion a makeshift (low) pressure container for Chow. No riskier than a bottle rocket. And it worked brilliantly. The Emperor was immediately able to descend from the surface and swim about under pressure. Clearly it was a gas problem. It took a further 4 sessions over 4 days to observe a sustained improvement and Chow was eventually returned to the  tank with it’s pretty things after a few days.

From not being able to swim much at all, and lying on his/her side all day and night, I am happy to report that Chow is now happily swimming midwater again and eating well. While a soda bottle makes for a rather less than suitable vessel, it did work and Chow now enjoys a more comfortable existence.

The reason for this story? Not all fish that look dead are dead and HBOT is by no means limited to humans. Pet and specifically small animal HBOT is growing in popularity and we also hope to develop our service in the future to include this. In a lot of cases fish have a swim bladder problem which can be fixed with specialised food, temperature changes, temporary withholding of food and of course … hyperbaric treatment or increased pressure. It wouldn’t be the first time a little goldfish has gone for a ride in the chamber and most certainly won’t be the last.

With lockdown continuing there is no shortage of home based projects and we hope to build a small low pressure pressurised container which can take a gold fish bowl for future use.

Keep well and safe everyone.


©Hayden Dunstan


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