A Breathing Apparatus For Fish During Surgery




Just like humans, animals need medical attention too. Artificial limbs, surgical tools and specialized equipment are all tools that veterinarians utilize when treating animals. It is difficult to identify what needs are important for animals since communication and language are not something that can easily be done.

The Vancouver Aquarium works closely with many marine animals and I have been working with them to create a medical device that will benefit both the animals as well as the vets.
The Vancouver Aquarium has recently worked been in the news with high profile animal rescues such as the False Killer Whale named Chester that was found near death and is currently doing very well, and giving a false eye to a fish that was a target of other fish for being easy prey.

Because I am working with animals and surgery, the veterinarians were not only my experts but also my co-creators. The vets at the Vancouver Aquarium have been giving me a lot of feedback as well as advice on how the animals interact with them and how they behave.

On my first trip to the Aquarium, Martin showed me around and we discussed possible design projects. These included:

– An x-ray stand that made it easier to move and lift while off-site and with large animals

– Something to hold a fish for injections without the need to anesthetize it

– An anesthetic tube to keep water going over gills during surgery

– An endoscope for retrieving swallowed objects within a bag to reduce scraping during removal

Martin Haulena

DVM, MSc, Dipl. ACZM Staff Veterinarian


Experts & Veterinarians

Justin F. Rosenberg

Veterinary Fellow

Ruby Banwait

Primary Aquariest / Caretaker

Chelsea De Colle

Senior Veterinary Technologist





Great care was taken to interact with live fish from the Aquarium. Only fish that already needed to undergo a procedure were used in order to reduce stress for the animals.

My co-creators consisted of fish. 2 of these fish were live fish from the Aquarium that were undergoing procedures while the other 2 were salmon heads from the market that allowed me to explore without fear of harming the fish.

The live fish recovered from their surgeries and can be seen swimming around in their tanks at the Aquarium.

Just Keep Swimming

Yellow Tail Rockfish

Copper Rockfish

Smokey the Salmon I

Smokey the Salmon II


Fish Surgery

Fish are anesthetized in a small tank by dissolving medication into the water. Once the fish is asleep it is placed on the surgical table with a sponge to keep them moist. (1) The medicated water is pumped from below the table and through a tube that is placed in the mouth of the fish. The water is also oxygenated in this bottom tank. The water needs to flow over the gills to allow the fish to breath a well as keep it asleep. The water falls through a hole in the table and back into the tank below.

After surgery, the fish is placed in a fresh tank of water to recover and slowly wakes up where it can be observe before being returned to their regular tank.


Gills function similarly to lungs. They have many small filaments that form a huge surface area where oxygen can be gathered from water as it flows over them. (1 & 2)





Some places put tubes directly into the gills but this can be harmful and rip the gills. It also doesn’t provide flow over the entire gill and doesn’t provide much oxygen.

DanielGleiberman EmilyCarr2015

A Yellowtail Rockfish undergoes surgery. It was startled when removed from his tank but was easily distracted with food and then sedated. When he awoke later, he was sleepy but not aware or scared.


Water is sprayed through the mouth and from the outside to flow over the gills of the fish to help it breathe.


My second trip to the Aquarium I observe two fish surgeries. The first was for a Yellowtail Rockfish that had a rash. This type of fish is common in the Aquarium and exploratory surgery is frequent to maintain the health of the fishes that live there. This fish needed to be moved into several positions that made it difficult to irrigate the gills. The second surgery was on a Copper Rockfish that had air in its bladder.

Both of these fish recovered from their surgery after about half an hour after it finished. The Yellowtail had a follow up procedure during one of my subsequent visits and had begun improving.

Fish Surgery

DanielGleiberman EmilyCarr2015

Co-Creation & Observation

12 Equipment
The equipment used at the Aquarium was mostly common materials.


Parts need to be small and flexible for use on a variety of types of fish. It needs to be low cost and durable as well as easily washed. PVC pipes and rubber tubes are available at most hardware stores and can be replaced quickly for little cost.

Surgery is done on a large sponge (1) to keep the fish wet while water with dissolved anesthetic is cycled from beneath (2) and sprayed through the fish’s mouth over its gills. This tube needs to be moved back and forth over both sides of gills and requires a n additional tech to be resent during surgery in a small room.

A tracheal balloon (3) was tried to keep the tube in place in the mouth but sharp teeth popped it after only a couple of uses. Splitters and sprayers have all been tried but fail to stay in place and fail to target the gills. (4)




After surgery is done, the fish is placed in a tank of recovery water with extra oxygen until it wakes up. Water is swept gently into its mouth until it begins breathing on its own.

Return To tank

Once the fish is partially awake, it is returned to its tank to wake up and swim around. In some cases the fish is placed into a secondary tank to remain isolated if it needs to avoid other fish or if it needs to be observed longer.


Surgical Area

The surgical Area at the Aquarium is a small room with shelves filled with tools and medicines for different animals. The area has x-ray equipment, ultrasound, and laboratory tools for research. A larger room next to it has room for larger animals but most procedures for larger animals is done in or around their tanks. All the equipment needs to be lightweight and mobile.

Reducing the Number of People

In order to irrigate a fish during surgery, an additional vet tech is needed. This becomes a problem in such a small area and means there are more hands getting in the way.


I simulated being a fish out of water with a breathing tube by putting myself underwater with a breathing tube.

Empathy Study


Animals have different needs than humans. They also can’t communicate their needs with us very effectively. In order to better understand what type of problems I would encounter while designing for animals, I needed to experience them for myself. I spent some time observing underwater animals and researching how they behave. The whole world is different under water, from the way you breathe to the way you move, how sound travels, where you store your food, everything.

There was also the problem of communication during testing, how would I know if the animal was uncomfortable or in pain or simply bored? I tried all sorts of activities to help understand what animals experience.

Behavior Observation

For 3 days I observed and shadowed animals. On the first day I observed fish and cetaceans at the Aquarium and made notes about how they interacted with each other. I also observed some of the animals that were recovering and getting surgeries. I learned that for most fish, it was easy to keep them happy with food and that they don’t really care what is happening most of the time but with mammals, you needed to earn their trust and understand that they are in charge until they allow you to help.

For the last 2 days, I shadowed my cat (Tim). First in the apartment to understand his normal behavior, then I took him outside and to the pet store to see how he reacted to human activities such as shopping or getting a haircut.

Most of the day was spent napping. This was actually much more difficult than expected as there was not a lot to do and I got bored very easily whereas my cat enjoyed it a lot.


Not being used to going out, my cat was mostly curious but also very skiddish around people and noises that were unfamiliar. It was very apparent that this change of environment was not an easy thing. He did enjoy his haircut and grooming though.


Empathy Study 2

Understanding Animals

With the help of the Aquarium I was able to interact with animals and see how they communicate. (1) Communicate was difficult but trained animals such as the sea lion pictured here had more patience and at least a small amount of knowledge of what I was trying to say. Other animals such as fish had little to no interest or understanding.

I also went underwater (2) to see how animals needed to move differently than those that move in air. Range of motion was different and the ability to move up and down as well as forward and back made the ability to move very different than I was used to.

Designing In The Dark

By trying normal activities while blindfolded, I was able to experience living with a disability and by observing my girlfriend doing the same, I was able to see how people act when they have lost their sight. (3) When you lose a sense that you are constantly relying on it is difficult to do simple activities such as walking around or trying to identify an



I originally wanted to build the Endoscopic Retriever as I wanted to work with large animals but it had several shortcomings. It would be very expensive and very difficult to test. I decided to build a Gill Irrigation Device as it had a larger potential benefit and be much more useful for the Aquarium.

Endoscopic Retriever

My idea is to design a cheap alternative to attach to the end of the endoscope that will cover the object and can protect the inside of the animal from any sharp ends or rough materials. A cheap disposable sheath such as a condom would be useful in helping retrieve objects safely.

Fish Surgical Table

This design would be an entire table for the vets to perform surgeries on. It would have a shape that allows for more space around the table in a small room, be easily transported, have built in lighting and a mister to keep the fish hydrated, as well as a tube to irrigate the gills and keep the fish sedated.

Gill Irrigation Device

During surgery, fish need to be out of the water but they still need to breathe. They are given water through a tube that must be waved back and forth to distribute water over their gills. This design would provide a way to irrigate both gills while holding the tube in the mouth and reduce the need to have an additional tech their to hold it.

3 Design Options

DanielGleiberman EmilyCarr2015

Flow control knob for easy pressure changing and to stop water

Grippy notches to hold in place

Flexible cone comes in different sizes and shapes for different fish and fits on snuggly

Flexible cone shape conforms to mouth

Mouth needs to be completely covered so that water doesn’t leak out

Gills Need constant water flow

What It Does Sharp teeth may cut softer materials


The Concept

Breathing Out of Water

Taking a fish out of their tank can be difficult, I aim to find a way to help them breath while undergoing surgery, which usually takes place on an operating table out of the water.



Water Delivery

There are several ways to deliver water within a fish’s mouth. I needed to consider the fragility of gills but still have something that fits in the mouth and provides enough pressure to distribute water all over. I really wanted to use a balloon type of system with a strong but flexible material that would inflate with water. (1)Flexible materials such as silicone or PET would work to direct the flow of water while blocking the opening of the mouth.


I wanted to incorporate other possible functions into the device so that the vets could use it more universally. Directional and different nozzle tips were a possibility. (2)

A shut off valve on the device was an important consideration so that flow rate and pressure could be controlled. (3)

A splitter was also important so that water could also be sprayed over the fish to keep it hydrated while keeping only a single pump. Using a quick connect system with devices such as splitters and sprayers already incorporated made it easier to include them in the overall design. (4)


Hose connectors

– Quick release and attach – Cheap & easily available – Durable

Dental Tools

– Hold hose in place
– Must prevent water from leaking – Stand up to sharp teeth


– Located in cheeks
– Need constant flow of water
– Gentle water flow to prevent injury

Tracheal balloon

– Doesn’t stand up to sharp teeth – Expensive
– But it does hold hose in place

Design Criteria

Primary Design Criteria

– Waterproof
– Saltwater & chemical resistant – Durable and teeth resistant
– Lightweight
– Adjustable flow rate
– Adjustable size/shape

Secondary Design Criteria

– Small / different sizes to fit into fish mouth – Flexible to bend to different shaped mouths – Inexpensive / easily replaced
– Grippy surface

– Non-porous / easy to clean – Flexible ball joint to spin

Tertiary Design Criteria

– Bright colored
– Easy to hold & handle
– Can be used with existing hose systems – 3D printed or molded with flexible plastic



How to Keep It in the Mouth

Reverse Clamp

A clamp with an adjustable width or spring loaded would keep the mouth open to different sizes. (1)

Rubber Stopper

A flexible stopper that can bend from a flat shape to fit into different sizes and shapes of mouth. This could be removable and replaced easily when it gets warn out.


Similar to a tracheal tube, a balloon could be made of a thick material and inflate with water. It could spray out of small holes at the end.


A hybrid of the stopper and a balloon, this would use flexible material in a ball shape but an open end. The water would be sprayed from a separate part while this conformed into the shape of the mouth to prevent water from escaping and to direct water flow towards the gills. It would be removable for easy cleaning and replacement. A grippy surface would keep it in place and stand up to sharp teeth.


Sometimes the best way to find a solution is to take a step back from the problem. Working with tools from the garden, kitchen, and plumbing sections, we threw everything into a big pile and started to mix and match. Inserting things where they shouldn’t be and shoving stuff into a disembodied fish mouth.



Bits & Pieces

Before starting to build, I needed to know how similar tools functioned. I took apart hoses and shower heads, garden sprayers with flow control, straws, tubes and anything that distributed water.

(1) The ball joint on a shower head can allow flow into any direction and allow for full rotations. This would be beneficial for the vets to reduce tangling while moving around the fish during surgery.

(2) Reinforcing angles help to keep this sprayer from bending or breaking when being used.

(3) A wide spraying head with many holes for water would help distribute water while also increasing the amount of oxygen.

(4) Spring loaded triggers used on garden hoses can help to control the rate of spray but require constant pressure. Twisting the end can change the flow rate and pressure.


Hoses & Sprayers




Initial Prototyping


My initial prototypes were made of modeling foam with bits of tube in order to visualize my sketches. Some of these include dual heads with individual swivels, rubber stoppers and bumper pads to put on a clamp

Taking Things Apart

By taking things apart I could better understand how different parts functioned. I researched ball valves and splitters as well as spray heads and hoses.




CAD Prototyping


(1) There were many parts of my design that I modeled that never ended up getting made or didn’t work in the prototype stages. I had to work with interlocking parts and attachments. This helped me to understand which parts could be easily produced at home or 3D printed and which parts would need to be manufactured with different methods such as injection molding.

I also had to figure out tolerances of materials and stretch.

3D Printing

(2) I used 3D printing to make rapid prototypes to test materials, tolerances, sizes, and shapes.

After cleaning up my initial 3D sketches and models in CAD, I was able to 3D print them in different sizes with different shapes and angles.


3D prints were done in flexible PET, as well as rigid plastics such as ABS and PLS.

Print Failures Influence Design Shape

(3) There were a lot of print failures. I learned not only how to use 3D printers and different materials but also how different materials react to different conditions. For prototyping, this process was helpful but for a final product, more expensive and more exact processes would be needed.


Testing Different fish have different sizes and shapes of mouths so I needed to

find something that would work for a variety of types of fish. (1)


Keeping water in the mouth and flowing over the gills was a particular problem I needed to solve. Directional tubes could target the gills but may not work best. I would need to aim water at the gills while also keeping it in the mouth. (2)



Lift & Clamp

This prototype was to use grippy material and an adjustable lifter to stay in place in the mouth while adjustable moving arms target the gills. This proved to have too many parts and pieces to easily clean and keep track of.

Keep the Water In

The sides of the mouth were left uncovered and any water that was not hitting the gills initially was leaking out of the mouth.



Ribs on the outside provide places to grip and keep the piece in place.

Taking inspiration from dental tools and snorkels, this design works like a funnel to block all open parts of the mouth while water sprays against it. The shape also directs the water towards the gills.

Pop On, Pop Off

This design uses a snug fit and ring to stay on a sprinkler head. It can rotate freely but there are no small parts.


Made of flexible PET, this rubber-like material can stand up to sharp teeth without being hard enough to harm them. It can bend to fit the shape of the mouth and flex to keep its position in the mouth.

An additional piece of plastic for the fish to bite down on. This would help to keep the mouth piece in place.


Bite Down

DanielGleiberman EmilyCarr2015


Flexible material is soft and doesn’t harm the fish. It is capable of adjusting to different sizes and shapes of mouths but stiff enough to keep its shape and direct water towards gills.

Soft & Strong

The soft PET is strong enough to stand up to the sharp teeth that would be rubbing against it while not cutting or scrapping them. The material is non-toxic and water proof. Although the plastic I used will break down over long periods of time in water, a more expensive version can be medical safe. This isn’t entirely necessary at this point as the head is meant to be easily replaced and will only be used for short amounts of time during surgery rather than submerged 24/7.


The material is translucent to help see the water flowing within and easily detect if there is a blockage.




Throughout the process we presented our concepts and progress. I found that I needed to keep my presentations less cluttered and move my final piece front and center. I received a lot of feedback about explaining the concept more as it was very different than the human targeted designs that were more aimed at comfort and improving quality of life rather than as technical tools.


Through feedback I learned that I needed to allow my design to be more intuitive and user friendly. It needed to be immediately apparent how to use and what to use it for.



More Testing

Straight Out of the Horses Fish’s Mouth
Different shapes had different pros and cons but ultimately a single, but flexible shape worked best at filling the contours within the mouth.

Size and Shape

I found that my design was too large for smaller fish and too strong to bend in place easily. Designing smaller items would influence the final manufacturing method as it would require more precise and smaller parts. This would likely be accomplished with injection molding.



The smaller design was able to be used more effectively as it provided more flex and could more easily fit. Water still leaked out of the mouth rather than all of it going over the gills. This was due to extra room left for flexing but would also be reduced when used with the actual flow part.

One Piece At a Time

Since the spraying head didn’t need to be tested in place, we put the mouthpiece over the existing tube so that we could see what was happening. The mouthpiece stayed in place effectively and blocked most of the water from escaping and didn’t harm the fish.

Smaller & More Flexible


The less parts that could break the better. Less parts also means less to clean and less to potentially break. The design consists of 2 main parts. The first is a mouthpiece, which is a flexible material that goes into the mouth that directs water towards the gills while also keeping water in the mouth. This is easily removed for cleaning or replacing. The second part is the sprayer, which consists of a shower-head like end, a flow-rate control in the middle, and an attachment on the end that can be connected to a hose either by quick release or by conventional hose screw.


Keep it Simple


Twist & Click

The only moving parts are twisting ones. The mouth piece pops onto the sprayer but can still rotate to accommodate moving the fish.

The top of the sprayer has an adjustable flow-rate that can be easily controlled on the fly.

The quick release was dropped in favor of a standard size screw lock for a couple of reasons. For one, it is more universal and can be used with any hose system. Second, it was easier to manufacture, with a shape that was easier to produce using various methods such as 3D printing and injection molding. Lastly, it is still compatible with the quick release system thanks to an adapter piece.


The quick release system can be clicked into place for easy use. By removing this from the sprayer head, it becomes easier to use with a standard hose system if needed.

Moving Parts


Flow control knob for easy pressure changing and to stop water

Final Piece

(1) Made of a strong but flexible plastic, this part goes inside the fish’s mouth and keeps the water from leaking out. It holds the whole device in place and makes sure the water goes towards the gills. It can rotate to prevent tangling.


(2) The main body of the device, the sprayer has a flow control valve to turn on and off the flow of water while also being able to control the pressure of the water to adjust it for different fish.


(3) The end of the Sprayer, this has a screw that fits into most standard hoses. A quick connect can be added to allow for use with more parts.


Flexible cone shape conforms to mouth


Final Piece

Final manufacture of this gill-irrigator, or “Gill-igator” for now remains in small production but I hope to expand on it and have it injection molded and in the market.

A second prototype will be given to the Vancouver Aquarium and used over the summer for long term testing. After that, I will make any small additional changes that may be needed. I will continue to keep in contact with the Aquarium and I hope to work with them for my Grad Project on a similar device.


If the long-term testing is successful I will meet with a patent lawyer and begin the journey to mass production. Hopefully this device can help aquariums and marine biologists around the world to make performing surgery on fish much easier.

Where To Now?


Thank You

Thank you to Anne MacCallum, Ian Denison and everyone at GF Strong rehabilion center for your insight into assistive care. Thank you to the girls from Snugvest and all of the people who came in to critique our class. Thank you to the 3rd year ID class for constant feedback and ideas and especially thank you to Eugenia Bertulis for putting up with me being constantly behind schedule and allowing me to work outside of the norm for this project. Extra thank you to my girlfriend Elena Syrovatkina for helping me with all of my empathy studies, making sure I ate and slept, and gave me feedback the whole way.

More Thanks

I would like to give a huge thank you to all of the staff at the Vancouver Aquarium that helped me out with everything during this project, from showing me around and how everything works to introducing me to the animals. Special thanks go to Justin Rosenberg, Ruby Banwait and Chelsea De Colle for their involvement and Martin Haulena for putting up with my countless emails and finding time in his schedule for me.

Arrr Arr, Blub-Blub, Meow-Meow

Thank you to all the animals that let me hang out with them and learn from them, including Tim the cat, Tikvah the sea lion, Chester the whale (who didn’t really help but gave me an appreciation for the sheer size of some of these animals) and the numerous fish that helped me test everything.

None of the animals that were alive were harmed however, the two salmon heads I got from the market started out dead and went on to be someone’s very delicious dinner.