Tube / Force Feeding Fish

Tube Feeding Techniques for Fish

Jay Hemdal
c. 2021

tube feeding kit.jpg

Syringe with catheter attached.


Here is an all too familiar scenario: an aquarist faced with trying to care for a new, expensive fish that tragically refuses to accept any food. Common sense dictates that fish need food in order to survive. The frustrated aquarist may try different foods, (“It just must not like what I’m offering it!”). They may add various “food attractants” that rarely work. The aquarist may play the waiting game, “It will begin eating when it gets hungry enough, and so I’ll just keep trying.” Many aquarists deny there even is a problem, (“I haven’t seen it eat for six weeks, but it must be eating something – probably when I’m just not looking.”). Most of this is wishful thinking – a fish that doesn’t actively pursue and consume the food you offer it is going to have a problem surviving in your aquarium for the long term.

To determine exactly why a particular fish isn’t feeding, a bit of analytical work is in order. Anorexia (lack of feeding response) in fish can stem from a variety of causes, and thus has many potential solutions – with only one best solution for each case. In addition, there are some causes of anorexia in captive fish that have no reasonable solution, and therefore are hopeless:

1) Is this species of fish known to be a poor feeder in captivity? If it is one of the “impossible to feed” species – it may never begin feeding on its own and tube feeding it will only prolong its life, not allow it to thrive and grow.
2) Has this individual fish fed well in captivity in the past? If it has fed before, what has changed to make it stop feeding? Tube feeding should only be considered in this case if rectifying the problem will take more than a week, otherwise it is usually better to simply let the animal fast until you fix the problem and it begins feeding on its own again.
3) If the animal is suffering from a disease, is the prognosis good enough to consider tube feeding it during the treatment?
4) Does the animal require a treatment with a medication that cannot be administered except by tube feeding?

Force feeding or tube feeding are both terms that describe an attempt to give sustenance to an animal that refuses to accept food on its own accord. How long can a fish go without food and still survive? Some larval fish at critical stages of their development may starve to death in less than a day if the proper food is not made available to them. At the other end of the spectrum are cases where moray eels have gone on self-imposed fasts lasting as long as 8 months, and then spontaneously began to feed again. A large saddleback butterflyfish refused all food for over 120 days and when it finally began to feed on standard aquarium fare, it didn’t look any thinner than the day it arrived from the collector. One ailing pinecone fish stopped feeding, but otherwise looked very healthy. When it finally died 6 months later, during necropsy it was noted that its body cavity was still filled with quite a large amount of fat deposits. Generally, unless there is some underlying acute disease or water quality problem, otherwise healthy fish can undergo long periods of fasting and still survive – if the cause of their anorexia is eventually resolved.

The food recipe used in tube feeding changes little from fish to fish. The basic premise is to prepare a food that is liquid enough to easily pass through the feeding syringe and tube, but thick enough to carry a high number of calories to the animal’s digestive track with the least amount of water. Avoid trying to mix a “super food” chock full of extra minerals, vitamins, fats and protein – stick to a mixture that is similar to the animal’s normal diet. Regular aquarium flake food blended with an appropriate amount of water suffices in most instances. The amount of food to administer is difficult to judge, but generally, an amount on the order of 2 to 4% of the animal’s body weight is sufficient. This should be just enough food to cause a slight distension of the animal’s belly. Too much food will usually result in regurgitation – often nearly the entire amount that was fed. Don’t be too concerned about the sterility of the food mixture or the feeding equipment – fish always ingest some tank water when they feed normally, and this obviously isn’t sterile. The food should be freshly made and the equipment washed well between uses, but sterilization isn’t necessary.

Tube-feeding equipment varies depending on the size of the fish being fed, but normally consists of a syringe and a flexible plastic tube. Feline urinary catheters or avian tracheal tubes can be used for small fishes. Larger fishes can be fed using airline tubing or horse catheters. Many prefer to use a Luer-lock syringe so the tube is held more securely to the syringe body, but the tubing can also be glued to the syringe with cyanoacrylate glue (Noga 2000). The tubing needs to be rigid enough to pass into the fish’s stomach but soft enough not to injure the lining of the gastrointestinal tract (Noga 2000). It helps with insertion if you first bevel the end of the tube. The tube must also have marks on it at regular intervals so that you can more easily judge the depth of insertion.

The actual tube-feeding technique used is difficult to describe, and a person’s first few attempts are sometimes met with failure regardless of the instruction given. In most cases, the use of an anesthetic such as MS-222 is required to quiet the fish so the tube can be inserted. In some cases, the fish can be manually restrained for the few seconds it takes to administer the food. It is generally best to first hold the tube alongside the fish’s body and mark the length needed to reach the center of the animal’s stomach. Holding the fish on its back, gently insert the tube into its mouth and try to locate the esophagus. If you are too far to the left or right, the tube will usually emerge from one of the opercula. If you have the tube positioned too high or low, it will often hang up on the tongue or vomer teeth in the roof of the mouth. Once the esophagus is located, gentle pressure is all that is needed to insert the tube down into the stomach. At that point, gently press on the syringe plunger and inject the food into the fish’s stomach. Gently withdraw the feeding tube and return the animal to a recovery tank. Keeping the animal submerged during the procedure and at all times afterwards minimizes torsion on the stomach and will reduce the chance of spontaneous regurgitation. The frequency of administering this procedure is a compromise between getting enough food into the animal while reducing the stress inherent with tube feeding. For example, a small marine angelfish might normally be fed two or three times per day, but tube feeding an animal that often is likely to cause chronic injuries that negate the benefit of the food being given. Furthermore, fish that have just recently been tube-fed are not likely to begin feeding on their own. Therefore, it is best to tube-feed small fish every second or even every third day, and always try to entice the animal to feed on its own just prior to each procedure. Some large predatory fish may only need to be tube fed once a week or so.


The following case histories will help describe some common scenarios where tube feeding has been used, showing cases that did and did not have a successful outcome.

Pinnatus batfish: Perhaps the first time this species of fish had ever been tube fed, this case was unique enough to be written up in an aquarium magazine (Hemdal 1985, 1997). In this instance, the animal eventually perished due to secondary infection apparently caused by handling during the feeding procedure. Still, the animal was kept alive long enough to actually show some growth derived solely on the food energy it was gaining by being tube fed, and it did eventually begin to feed a bit on its own.

Butterfly ray: As an aquarist for a major public aquarium, I had ordered one of these fish from a collector. Upon its arrival, my curator commented, “Too bad you didn’t ask me before ordering this fish – they always starve to death in captivity”. Wanting to prove that I didn’t make a mistake in ordering the fish, I began a three times per week tube feeding regimen for it. The animal actually began to grow as I kept up the procedure for two months. Ultimately, I became too comfortable with the procedure, and I was careless one time and inadvertently ruptured the animal’s stomach by inserting the feeding tube too far and it subsequently died of an infection.

Walking batfish: A group of these fish arrived from a collector and soon began feeding well on live mysids and brine shrimp. Previous experience with these fish told us that they are often severely infected with internal worm parasites. Our most common means of feeding anti-helminthics (de-wormers) was via medication added to gelatin food. As these fish wouldn’t eat that food, they were force fed a liquid food with an appropriate amount of Panacur added. The next day, all the fish were seen expelling dead worms from their vents and went on to be healthy aquarium inhabitants.

Garden eels: Apparently, due frequently being collected with chemicals, these fish often refuse to feed in captivity. In some cases, tube feeding them for a few weeks will keep them alive long enough that they will begin feeding on their own. The primary problem with tube feeding these fish is that you must use MS-222 to anesthetize the fish each in order to get it out of its sand burrow. Eels that are too weak to create a burrow generally do not survive no matter what you do for them.

Talma butterflyfish: This case was interesting in that the animal did not feed when it was first acquired, but soon began feeding on its own once it had been tube fed a couple of times. It then lived problem free for almost a year, and then suddenly for no apparent reason, stopped feeding. It was tube fed three times a week for two months, but never began feeding on its own again and was eventually euthanized.

Weedy scorpionfish: This animal had refused all food for 6 weeks after its arrival. After tube feeding it once it began feeding on live fish the next day and was soon converted over to sliced seafoods. This case was special in that the species is venomous so great care had to be taken during the procedure so that nobody got stung. For safety of the aquarist, the use of MS-222 anesthetic would be mandatory in cases like this.

Weedy seadragon: A very rare and valuable fish, this animal had been in captivity for two years when it suddenly stopped feeding on live mysid shrimp (the only food it would accept). It refused food for a month while it was treated with various anti-protozoan medications. It began feeding on its own for two days, and then stopped feeding again. This time it was suspected that the animal had developed a secondary bacterial infection. It was tube fed using a very tiny catheter during the four weeks it was given antibiotic injections. No anesthetic was needed, but inserting the tube through the animal’s long narrow snout was very difficult. About a week after the last injection, the seadragon began feeding on its own and has done well since then.

Force-feeding is a technique that can be employed on larger carnivorous fishes. A sedated fish is held on its back while its mouth is opened, and a food item of appropriate size for the animal is then placed in the back of the animal’s throat. A finger or semi-rigid tube is then used to gently push the food item into the stomach. In some species, such as anglerfish and eels, there are back-curved vomerine teeth in the throat that will actually grasp the food item and keep the fish from voluntarily regurgitating it. Be cautious in directly handling a fish during either of these two techniques, as some have very sharp teeth and, of course, some fish have venomous spines.

What are the drawbacks to this procedure? One problem is that until one develops a practiced technique, improperly tube feeding a fish may cause serious damage to the animal’s digestive system, or at the very least, will prove ineffectual at providing any sustenance for the animal. One can describe all the equipment, the food recipes, and when you should or should not attempt this procedure – but your results hinge entirely on how well you are able to carry out the process. This is akin to why some doctors, despite their similar training become surgeons while others prefer general practice. Remember, “Practice make better.” Perhaps the greatest cause of failure with this technique is picking a fish with an “impossible” prognosis: An animal that is dying from an unresolved protozoan disease is not going to be helped by a tube-feeding procedure. A fish that is within days of death from starvation is also not a good candidate for this technique. Knowing which fish to give up on, and which may actually benefit from tube feeding is of paramount importance to the aquarist.


References:

Hemdal, J.F. 1997. The red-rimmed batfish - revisited. Aquarium Frontiers On-Line September 1997 http://www.petchannel.com/aqfm/1997/sep/features/1/index.htm

—— 1985. The pinnatus batfish: force feeding. Freshwater and Marine Aquarium 8(10):18.

Noga, E.J. 2000 Fish Disease Diagnosis and Treatment. Iowa State University
Press Ames Iowa

 
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jtf74

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Interesting topic. I've wondered about this myself. I used to own snakes and sometimes one would refuse to eat and had to be force fed. It did work and the python started eating again. So why not fish?
 

vahegan

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Has anyone tried this with regal angels? I have lost quite a few of them, always the same story: they refuse to eat (when I offered food, they swim to it, but lose interest when they reach it, no matter what type of food was offered, and I tried everything) and gradually parish within one month. Also, in regard with MS-222 - what is the technique used for its administration, and doses? I think, pH needs to be stabilised at some value using a buffer, and then it is important how the fish is withdrawn from sedation. I can recall reading an article about using MS-222 for shipping fish, in order to reduce oxygen consumption and stress, but that was over 20 years ago...
 
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Jay Hemdal

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Has anyone tried this with regal angels? I have lost quite a few of them, always the same story: they refuse to eat (when I offered food, they swim to it, but lose interest when they reach it, no matter what type of food was offered, and I tried everything) and gradually parish within one month. Also, in regard with MS-222 - what is the technique used for its administration, and doses? I think, pH needs to be stabilised at some value using a buffer, and then it is important how the fish is withdrawn from sedation. I can recall reading an article about using MS-222 for shipping fish, in order to reduce oxygen consumption and stress, but that was over 20 years ago...
The trouble with tube feeding regals is that it doesn't get to the root cause of why they aren't feeding, so if/when you stop, they starve.

You dissolve the MS-222 in seawater at 75 to 100 ppm, depending on how fast and deep you want the fish to go. The fish cannot be held at this plane of anesthesia too long though, perhaps 3 to 5 minutes.

I usually do not use a buffer in seawater with MS-222, but I do with freshwater.

Jay
 

vahegan

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The trouble with tube feeding regals is that it doesn't get to the root cause of why they aren't feeding, so if/when you stop, they starve.

You dissolve the MS-222 in seawater at 75 to 100 ppm, depending on how fast and deep you want the fish to go. The fish cannot be held at this plane of anesthesia too long though, perhaps 3 to 5 minutes.

I usually do not use a buffer in seawater with MS-222, but I do with freshwater.

Jay
Thanks Jay,
I was on the impression that they were on the verge of starting to try taking food, but were already exhausted at that stage. I had once have one pick some seaweed that I had offered him, and I was so happy to see him do this, but I found him dead the following morning :( Also, based on a similar experience with reptiles, I recall that if they do not eat for long enough, they lose interest to food and would neglect it. By force-feeding you restart something in them, so I thought it might be similar with fish, But I never tried to force-feed the fish, I always considered them too delicate for the procedure. Thanks for the great tips, I may give it a try next time I face the issue.
 
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Jay Hemdal

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Thanks Jay,
I was on the impression that they were on the verge of starting to try taking food, but were already exhausted at that stage. I had once have one pick some seaweed that I had offered him, and I was so happy to see him do this, but I found him dead the following morning :( Also, based on a similar experience with reptiles, I recall that if they do not eat for long enough, they lose interest to food and would neglect it. By force-feeding you restart something in them, so I thought it might be similar with fish, But I never tried to force-feed the fish, I always considered them too delicate for the procedure. Thanks for the great tips, I may give it a try next time I face the issue.
Starting tube feeding too late can be an issue. I always opt to try earlier than later. What can happen is that in a starving fish, it utilizes its liver as a source of energy. This induces liver damage. Then, you force feed the fish and the liver damage apparently kills the fish. This can happen with any long term starvation case - possibly the case you mentioned. I once had a snowflake moray that went off food for 8 months. I eventually got it to take a goldfish and it died the next day.....

Jay
 

Dr. Jim

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I've been tube-feeding fish for as long as I've been a veterinarian (over 35 years) but you don't need to be a vet to do this (although being a vet makes it easier to obtain the supplies, in particular, the feeding tubes. I'm not sure if a place like chewy.com would have them or better yet, if you have a vet that you use, you may be able to obtain a tube from him/her).

I'm currently tube-feeding a hippo tang and made a short video (below). But first, let me side track a little and tell you about my nightmare move from N.J. to FL three weeks ago. After driving for 25 hrs with a 1.5 hour sleep (at a Tesla charging station) I arrived at my condo at 11 pm with about 60 bags of corals (frags) and fish that had been in bags of water/oxygen for about 30 hours. I was exhausted but knew I had to still hook up my RO/DI and set up a temporary 30 gal tank and screw together it's 2x4 stand. (The Moving Company would arrive 2 weeks later with my furniture, etc., and 100 gal tank, stand and equipment). BUT... after unlocking the door to the condo, I found that there was no electricity! I freaked out! I found a hotel at midnight to let me set up the tank, unbag all the corals/fish, etc....and I finally got done at 4am! The next morning I got electricity quickly and had to disassemble everything at the hotel, move it and re-set it up again!

Anyway, in the process, something happened to my hippo tang. It almost seemed like it suffered a "stroke" or some kind of brain damage based on the way he acted. He seemed strong but disoriented and I could easily catch him with my hand. I have been tube-feeding him every 2-3 days for the past 3 weeks now. I don't see much change but I'm keeping him alive and hope that he makes a turn for the better. I inject about 1.5 cc of a ground flake slurry. Here's the video:



It seems that every fish is a little different when tube-feeding. With most fish, it seems that it is easy to get the tube in the mouth but sometimes a little tricky to direct it down the esophagus to the stomach, but with this hippo, it was the opposite: i.e. difficult to get the tube in his mouth (because it kept it's mouth shut and it has little teeth) but easy to get the tube to pass down the esophagus.) Some fish, like copperbands and other butterflies are the ones I recall having the most difficulty finding the esophagus. Practicing on cadavers helps. I have never used anesthesia (and don't think it is particularly necessary). Certainly, not every fish I've tube-fed ended up pulling through it's illness, but I don't recall any dying from the tube-feeding procedure.
 

DrZoidburg

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Some times pressing under their jaw helps get mouth open. Spot on underside in between gills if that makes any sense. With small fish I like using a syringe with the titration tip. If you have any fish oil pills pop one open and lubricate the tip of syringe works great.
 
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Jay Hemdal

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I've been tube-feeding fish for as long as I've been a veterinarian (over 35 years) but you don't need to be a vet to do this (although being a vet makes it easier to obtain the supplies, in particular, the feeding tubes. I'm not sure if a place like chewy.com would have them or better yet, if you have a vet that you use, you may be able to obtain a tube from him/her).

I'm currently tube-feeding a hippo tang and made a short video (below). But first, let me side track a little and tell you about my nightmare move from N.J. to FL three weeks ago. After driving for 25 hrs with a 1.5 hour sleep (at a Tesla charging station) I arrived at my condo at 11 pm with about 60 bags of corals (frags) and fish that had been in bags of water/oxygen for about 30 hours. I was exhausted but knew I had to still hook up my RO/DI and set up a temporary 30 gal tank and screw together it's 2x4 stand. (The Moving Company would arrive 2 weeks later with my furniture, etc., and 100 gal tank, stand and equipment). BUT... after unlocking the door to the condo, I found that there was no electricity! I freaked out! I found a hotel at midnight to let me set up the tank, unbag all the corals/fish, etc....and I finally got done at 4am! The next morning I got electricity quickly and had to disassemble everything at the hotel, move it and re-set it up again!

Anyway, in the process, something happened to my hippo tang. It almost seemed like it suffered a "stroke" or some kind of brain damage based on the way he acted. He seemed strong but disoriented and I could easily catch him with my hand. I have been tube-feeding him every 2-3 days for the past 3 weeks now. I don't see much change but I'm keeping him alive and hope that he makes a turn for the better. I inject about 1.5 cc of a ground flake slurry. Here's the video:



It seems that every fish is a little different when tube-feeding. With most fish, it seems that it is easy to get the tube in the mouth but sometimes a little tricky to direct it down the esophagus to the stomach, but with this hippo, it was the opposite: i.e. difficult to get the tube in his mouth (because it kept it's mouth shut and it has little teeth) but easy to get the tube to pass down the esophagus.) Some fish, like copperbands and other butterflies are the ones I recall having the most difficulty finding the esophagus. Practicing on cadavers helps. I have never used anesthesia (and don't think it is particularly necessary). Certainly, not every fish I've tube-fed ended up pulling through it's illness, but I don't recall any dying from the tube-feeding procedure.

Thanks for the video - it shows one thing I don't think I explained, it is best to hold the fish recumbent, and upside down. For this fish though, I would opt to use a feline urinary catheter, that red rubber tube is larger than I would have thought would work. However, it is softer than a cath, so perhaps that makes the difference?

I've never tried tube feeding a CBB, but the case I mentioned where I fed a juvenile pinnatus was just as tricky I think.

Good idea for trying the technique on dead fish first - practice makes better! The only thing that won't help with is the issue with regurgitation, releasing the fish slowly and carefully can help with that I think. I also feel that MS-222 helps with that issue, the fish doesn't struggle and the food seems to stay down better.

Jay
 

Dr. Jim

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Thanks for the video - it shows one thing I don't think I explained, it is best to hold the fish recumbent, and upside down. For this fish though, I would opt to use a feline urinary catheter, that red rubber tube is larger than I would have thought would work. However, it is softer than a cath, so perhaps that makes the difference?

I've never tried tube feeding a CBB, but the case I mentioned where I fed a juvenile pinnatus was just as tricky I think.

Good idea for trying the technique on dead fish first - practice makes better! The only thing that won't help with is the issue with regurgitation, releasing the fish slowly and carefully can help with that I think. I also feel that MS-222 helps with that issue, the fish doesn't struggle and the food seems to stay down better.

Jay
I forget the guage (French) of the catheter I am using but it is not much thicker than a feline urinary catheter and I've used it on smaller fish including butterflies. I think I would worry about the more rigid feline catheter puncturing something, but I'm sure one can "perfect" using either one. I found that even very small fish have an esophagus large enough to accommodate the red tube. I guess they are relatively large because they need a large opening to swallow their prey.

I never had issues with regurgitation (without sedation). Often, however, excess food will come out of their mouths but I believe that is because I tend to fill them up and probably sometimes overfeed (which apparently doesn't have any detrimental effects).

I never used MS-222. I never looked into where to get it.....but probably should have! I'm sure there were times I could have used it for certain procedures.

I should have mentioned in my first post, for anyone considering trying this..... the amount of time I held the fish out of water was a bit longer than I usually do (probably because of making the video). If I can't get the tube in within a reasonable amount of time I usually release the fish back into the container for 20-30 seconds and then try again.
 

Dr. Jim

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Why did you have to force feed the hepatus in the first place? Is he ill? I never seen one of them refusing food, they are usually voracious.
I explained a little in the original post. After being in a bag with O2 for 30 hours or more, something happened to him. Maybe he suffered from hypoxia which could have caused some brain damage which could explain his stupor-like condition. Or, perhaps a shock-like symptomology from stress???
 

NowGlazeIT

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As I said....you don't really need to be a vet to do this. (If you can get the tiny guage red rubber tube.....you can wait until you come across a dead fish and practice. It isn't real hard to do).
Oh I didn’t mean that literal. Just meant those that go the the extra mile to identify and treat sick/ infected fish.
 
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