Why do goldfish overeat to the point of death?

[larryngu 31]

I was just wondering why do goldfish overeat to the point of death? Any one knows or can guess that reason.

Is there a biological reason or some survival instinct?

Do other types of aquarium fish (other than goldfish or koi ) do that?

As far as I know, no other type of pet (other than fish) would fatally overeat. Am I wrong or right?

[dnalex 13,633]

I don't think that goldfish will overeat to the point of death. Why would you say that?

[LovelyChaos 869]

I think it is more, people feed their goldfish to the point of death. Goldfish learn to eat when they are given food. They see food they think to eat. If you are feeding them too much too often the goldfish will suffer and eventually pass away from an illness caused by the extra food.

[vwashbur 59]

I believe over eating would have something to do with the fact that goldfish only have an intestinal tract and lack a stomach. However, I don't think they would eat to the point of death... I imagine the only time death would come into play is if the goldfish is being overfed, which then produces excess waste and therefore builds up toxins in the water. If such an excess is created the cycle would not be able to consume it quickly enough, resulting in poor water quality. The poor water quality would then lead to health issues in the goldfish which could result in death.

I don't think a goldfish would die directly as a result of eating too much though. I could be wrong, but that's my two cents.

[Mlegion1988 44]

Excess feeding can also lead up to excessive build ups of protein and fat in their body that can literally start crushing their internal organs. Steve Hopkins at RG has written a great article on feeding. I believe I saw it posted somewhere around here.

[larryngu 31]

First of all my goldfish is fine.

Do and can goldfish overeat fatally in one sitting?

I accidentally overfed my koi to death one time.

I bought two baby kois and put them in my tank. I had a tank ornament where the kois could hid.

The kois just kept hiding in tank ornament for days. While they were hiding in their tank ornament , I tried to feed daily. Twice a day to try and entice them out.

So by the end of two days there were lots and lots of koi food in the tank. One of the kois did fatally overeat, in one sitting. That koi stomach got really big and a lot of the koi pellets were gone.

I raised the surviving koi for nine month and it triple in size. I eventually gave my remaining koi to my brother who had a koi pond.

So , what you guys are saying is that goldfish can't and don't overeat fatally in one sitting?

Edited October 18, 2012 by larryngu

[shakaho 6,312]

The famous "danger" of overfeeding is not because goldfish will eat themselves to death. They don't. Rather it's because goldfish, particularly when kept in too-small containers, can be poisoned by waste from uneaten food. Even if they do eat all of the unneeded food, they will poop most of it out, and again the waste will pollute the water.

[DieselPlower 2,123]

I don't believe a fish can eat itself to death in one sitting.

If one did die I would believe it was from another cause.

[larryngu 31]

To the moderators, if you see it fit, you can change the title of thread, lock or delete thread.

I don't want to be spreading misinformation or paranoia .

I always thought that goldfish can if they are fed too much at one time.

[dnalex 13,633]

Larry,

I don't see any reason why the thread needs to be modified, locked, or deleted. You posted a legitimate question, and you are getting responses. I don't see anything wrong. I don't think that you are spreading any kind of paranoia or panic.

In fact, threads like this serve to underscore the importance of regulation of how much food should go into a closed aquarium setting and water quality in general, since the fish can't escape the water that they are in.

In any case, to get back to the discussion, there are feedback pathways to control appetite, and this is certainly true in fish.

[JouteiMike 5]

I think this has more to do with feeding habits than goldfish simply eating themselves to death, but you bring up a good concern! It is important to try to feed your goldfish small portions, as often as you can throughout the day, to keep their digestive system and metabolism at a good working order. Kinda like us humans right? Isn't it much better to eat small, frequent, healthy meals and snacks throughout the day, instead of 1 large meal? Most wild animals are endlessly on the lookout for food, and in the wild, they are constantly grazing and munching. This goes expecially for goldfish, and in particularly because they don't possess a true "stomach."

So while it's important you don't overfeed your goldfish, it's even more crucial that you don't UNDERfeed them as well... Feeding large meals, spaced out, could lead to gorging - and I think this is what could lead to digestive complications. Think of it this way: since the goldfish don't have a true "stomach," the food they consume needs to navigate the skinny intestines, so you wouldn't want a large quantity plowing through at any given one time, this could lead to a blockage and constipation problems, especially with cheaper, lesser quality food with fillers, artificial ingredients, and poor fiber. So feeding smaller, more frequent meals and snacks to our fish will decrease the chance of constipation and blockage because there will be a smaller bulk of food making it's way through the digestive tract, at a more constistent motion.

Edited October 18, 2012 by JouteiMike

[orandafan1981 68]

i'm no expert but i think they constantly graze like little water cows because they don't have a stomach!?!

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[orandafan1981 68]

should have read all the other threads first, i'm just repeating what others have said.

is it right that food can sometimes swell inside the fish and crush their organs?

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[Jeana727 952]

My thought was that the danger is really not that they might "eat themselves to death" but that if like you said :"So by the end of two days there were lots and lots of koi food in the tank"....THAT might have been the problem. You want to feed what they can eat & not really leave ALOT of leftovers. I like a little food for them forage for but I would not want "lots & lots".

[JouteiMike 5]

should have read all the other threads first, i'm just repeating what others have said.

is it right that food can sometimes swell inside the fish and crush their organs?

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Never heard of food "crushing" organs, but you're right that the food can expand once inside the fish. Especially if it's a dry pellet. I always recommend soaking any dry pellet or flake for at least a minute in a cup of tank water before feeding your fish. Kinda like us humans, if we swallow a bunch of air or drink a beer or soda real fast, we end up bloated and burpy. And I don't see why the same principle can't be applied towards fish. Especially since a lot of fish, like the goldfish, don't have that true stomach where the excess air can be contained.

[Jeana727 952]

Just to add....I doubt it was them over eating that caused the problem.....it was most likely that food was added "until it piled up". This would make the water bad pretty quickly.

So, for a learning tool: Feed what they can eat in one "sitting"...usually pinches of food per fish would be fine!

[Helen 8,511]

Just to add....I doubt it was them over eating that caused the problem.....it was most likely that food was added "until it piled up". This would make the water bad pretty quickly.

So, for a learning tool: Feed what they can eat in one "sitting"...usually pinches of food per fish would be fine!

i agree.. left over food decays quickly and breeds bacteria. i would think that your fish died because of bacterial issues rather than overeating. if your fish had overeaten, displays of floating or sinking would be seen, this indicates two things but both related to swim bladder issues from constipation, 1. floating, 2. sinking depending of wether there was air trapped in the pellets or not.

if food was left in their tank uneaten for up to or more than 24 hours and depending on the temperature of the water, bacteria is quick to breed. if the food was breeding bacteria and the fish had consumed this, then it is very possible that the fish died from those causes.

also, if your filter was uncycled, the toxicity from Ammonia alone would be enough to kill a fish. slowly following the toxicity of Ammonia which burns the skin and fins of a fish, are the Nitrites. Nitrites will poison by burning the fish's gills and cause suffocation. the biggest killer after Ammonia, are the Nitrites. ie, if Ammonia does not kill the fish, you can be very certain that out of control Nitrites will.

[Daniel 5,668]

I've found this thread to be quite interesting, so much so that I've actually been looking for academic articles on the matter. I'm yet to find any, which lends credence to what everyone else has said in regards to water toxicity killing your goldfish and not some Monty Pythons-esque Mr. Creosote complex, but I'd be lying if I said I wasn't just a little curious to see if any studies have been done on fish overeating.

Edited October 29, 2012 by dan in aus