Do Round Bowls Make Goldfish Go Blind?

Status: Undetermined
CNN reports that the city of Rome has passed a set of laws to prevent cruelty to animals. For instance, dog owners will be forced to walk their dogs regularly. And round goldfish bowls have been banned because round bowls supposedly cause the fish to go blind. Specifically, the article says:

The newspaper [Il Messaggero] reported that round bowls caused fish to go blind. No one at Rome council was available to confirm this was why they were banned. Many fish experts say round bowls provide insufficient oxygen for fish.

I have never before heard this claim about the dangerous effects of round bowls. I tried to google "round bowls goldfish blind" to see if anyone has written about this, but no luck. However, depending on the size of the opening in the bowl, it does seem logical that the fish may not get enough oxygen. And if they don't get enough oxygen, maybe they'll go blind (shortly before they die).

Incidentally, I'm totally in favor of laws forcing people to walk their dogs. I hate it when people (such as my neighbor) keep their dog chained up in their yard all day, every day.


Posted on Tue Oct 25, 2005


I doubt that round bowls make fish blind. There haven't been any studies done on it that I know about.
Posted by Dany  on  Tue Oct 25, 2005  at  12:19 PM
Maybe it's because there's no flat surfaces to reflect, the fish forgets that's in a bowl and thinks it's really just swimming in the room. Then being disoriented, it . . . .ah nevermind!
Posted by Joe  on  Tue Oct 25, 2005  at  12:54 PM
Put the little bstrds on treadmills!

Siamese Fighting Fish are sold in round fishbowls, stay in the pet store forever but they can still see other fighting fish. That part's bogus, but the first one is impossible to enforce.
Posted by Craig  on  Tue Oct 25, 2005  at  01:34 PM
:) just feed them to ur oscar and dont worrie if they go blind..
Posted by draven151  on  Tue Oct 25, 2005  at  03:47 PM
I have kept and bred many, many fish over many years, and have read very extensively about captive fish, and I can tell you pretty conclusively that keeping a fish in a round bowl will not cause the fish to go blind.

That's not to say that keeping a goldfish in a small bowl isn't cruel, however. I think it's one of the most common forms of cruelty against pets around. In the aquarium hobby, we refer to those little bowls as "goldfish torture chambers."

You see, goldfish grow to be big fish (a full-grown goldfish is about a foot long), and they have higher oxygen requirements than most pet fish, so one will be very crowded in a bowl if it's any smaller than 10 gallons or so. You might get away with keeping a small juvenile goldfish (2 inches or less) in a smaller bowl (say, 2 gallons) if you change the water very frequently, but you'd still need a bigger tank to move the fish to when it grows up-- which it will, if it lives long enough and you don't stunt it through filthy water and other bad conditions. What's that, you've never seen a foot-long goldfish? That's because most of them never get a chance to get that big. A goldfish's natural lifespan, by the way, is several decades. How many have you known of that lived that long?
Posted by Big Gary in Dallas  on  Tue Oct 25, 2005  at  05:15 PM
I had one that made it to the foot long mark, but then I left the country and my parents didn't take care of it as they said they would...
Posted by Raoul Duke  on  Tue Oct 25, 2005  at  05:36 PM
fish don't see that well anyway
Posted by Blood For Nothing  on  Tue Oct 25, 2005  at  06:30 PM
Big Gary, you rock! You said, so eloquently, exactly what I wanted to say! Rock on, dude!
Posted by thephrog  on  Tue Oct 25, 2005  at  07:51 PM
I love Big Gary too. Eloquent sanity! 😊

I'll just add to his comment that the majority of people keeping fish in bowls are not up to cycling tanks or maintaining water quality. On my pet site, we ALWAYS recommend the biggest tank a beginner can get.

Simplistically: Say a fish produces X amount of waste. X is going to be 10% of the water in a small bowl, but only 1% in a large tank. More water means more margin for error.

As for going blind, I've never seen or heard of that, and have kept fish for decades. I've even had them in bowls, though never when I could afford better, and always with strict water maintenance.

Hooray for Rome, though! I doubt it's all enforceable, but at least people will be thinking about it!
Posted by Steph  on  Tue Oct 25, 2005  at  09:39 PM
Oxygen in the water is influenced partially by the amount of surface area, but it's also influenced by aireation (water bubbles from filter systems) and the quantity of fish compared to the amount of water. I've seen some very large 'bowls' of fish. Public aquariums often have huge rounded swimming areas for sharks. A local mall has a massive round 'bowl' that goes floor to ceiling, full of expensive saltwater fish. These aquariums are well aireated and filtered and are not overcrowded and the fish do well in them.
Posted by Crazygirl  on  Wed Oct 26, 2005  at  12:29 AM
Very interesting, but I wonder why I cannot find any reference to this by-law anywhere in the website of Il Messaggero nor in the City of Rome's website.
Posted by Enrique  on  Wed Oct 26, 2005  at  04:38 AM
They're a damn fish. Who cares?
Posted by Carl  on  Wed Oct 26, 2005  at  05:54 AM
I have to disagree about the requirement to walk the dog. Not every dog needs to walk for exercise. While I agree that keeping a dog chained up or cooped up in a small apartment isn't good, having a yard for them to run free can be better than a walk. We never walk our two boxers. One of them has never been good on a leash, no matter how much training he had. But we do have a good sized yard that they can run and run and jump and fight and play and run some more. Absolutely no need for walks for them. We let them out all year round except when it's really wet and rainy, sometimes nearly all day long.
Posted by AnnMarie Johnson  on  Wed Oct 26, 2005  at  06:43 AM
I've seen this report on a news website, well it is a general website but it does have news articles, that isn't connected with CNN. If it's a hoax, it is getting spread around. Enrique, how long does it take for a government to post laws on their website? In some cases, maybe forever, but how long after this set of laws were passed was it when you checked? As far as the newspaper, that is more serious. I would presume that a newspaper would have their website up to date. Dogs are too loyal and loving to mistreat. Anyone with a dog should exercise the dog often. Take it for a walk, it's good exercise for you too.
Posted by Christopher Cole  on  Wed Oct 26, 2005  at  08:21 PM
My first question was, "What is 'round'?"

I've seen bowls that were round vertical, with flat sides and a small top opening. I've seen bowls that were round horizontal - only about 4-6 inches tall but 12 inches across. Those have a good size opening. I've seen several types of spherical bowls. One had a tiny opening, one had a very generous opening. One was a "Bio-Orb" bowl. Its opening was smaller, but it had a very advanced filtration system and was well aerated. So, which type of bowl are they banning? Wouldn't it just be simpler to TEACH people how to take care of their animals rather than regulating the whole mess?
Posted by Liz Marr  on  Thu Oct 27, 2005  at  09:41 AM
Well, if you see everything through distorting glass, you might develop eye problems, right?
Posted by greg  on  Thu Oct 27, 2005  at  06:35 PM
It's a fish! The dog idea makes sense because it's been shown that dogs that are taken out and socialised are much less prone to aggressive beavhiour than dogs that are locked up, but for god's sakes! It's a fish!
Can it even see outside the tank?

Can it remember that it saw outside the tank?

Even so, what is round? do they mean 'perfect circle' round, or as in, 'it cann't be any shape that has one continuous edge' round?
Posted by Libre  on  Thu Oct 27, 2005  at  08:58 PM
Libre: fish are living beings too, and deserve decent care. From the article, it seems that Rome is trying to legislate basic pet care. I don't know how they'll successful they'll be, but it's heartening to see someone try, since so many other countries will only step in if there's actual documented animal abuse. Many people think "it's only a fish" but I hope the people in Rome who think that way will now think twice before getting a pet they consider disposable.

I'm not an animal rights person, but I am an animal welfare person. I'm glad to see someone at least try this.
Posted by Steph  on  Thu Oct 27, 2005  at  09:29 PM
Fish are not disposable pets, as Steph said (rightly so), and do deserve decent care. That includes a tank big enough for them to grow. They have a genetic imperitive to get to their full size, and if not given enough room they will die. The majority of the time this is true. If you think a fish is a disposable pet, please don't buy one! That's all there is to it.
Posted by thephrog  on  Fri Oct 28, 2005  at  04:30 PM
It's simple: The round bowls remind the goldfish of boobies, and so they end up masturbating more. I bet they go blind AND have hairy fins.
Posted by Joe  on  Sat Oct 29, 2005  at  01:24 PM
Regarding your neighbor's dog; Please talk to your neighbors about the dog and let them know that it is considered a cruelty to chain the dog all they long. If they don't do something about it, then you should report them.
Posted by Mora  on  Wed Nov 09, 2005  at  01:00 PM
You guys all sound really confident and that's reassuring but I know this guy who works in an aquarium- he says that round goldfish bowls are fine for smaller fish (catfish, daniels, tetras etc.) but they drive goldfish insane with pain because the distortion of the bowl gives them migranes and eventuallly leads them to a very painful death in a few weeks or so which sure makes sense as to why MY fish keep dying...
Posted by bazza  on  Sun Nov 20, 2005  at  11:26 PM
I don't know about causing blindness, but goldfish, who can live 10-30 years if given the chance, live extremely short lives inside goldfish bowls. The water, which is usually room temperature, contains less oxygen than cold water (which is ideal for goldfish). Fish waste accumulates at an astonishing rate, with nowhere to go. Owners would have to empty out the bowl and fill it with fresh declorinated water at least once a week, if not more.

Goldfish will grow between 10-14 inches (2 feet or longer for Koi), require approx. 2 gallons per inch of body. A round goldfish bowl isn't appropriate for any type of fish, not even bettas because bettas are excellent jumpers.

The average goldfish would need a 20 gallon tank, just for himself, with excellent filtration.

They're not dying of blindness, they're dying of choking on their own feces. Something that should be banned by law since its incredibly cruel.
Posted by Laura  on  Wed Jan 18, 2006  at  02:57 PM
Goldfish are members of a genus in which the fish have a special "labrinthine" organ that allows them to draw oxygen differently than other fish. Which is why they (as well as Bettas) can reside in a bowl with no aeration. So, they will not go blind from lack of oxygen. Can fish even go blind?
Posted by sarah1348  on  Thu Jan 19, 2006  at  02:12 PM
No, goldfish are NOT labyrinth fishes and they most certainly do NOT have a special air-breathing apparatus. They breathe water through their gills, the same as most fishes. Any aquarium book will tell you as much. Goldfish are cyprinids, which is to say that they belong to the carp or minnow family, which is the most widespread family of bony freshwater fishes in the world. They are closely related to common carp.
Goldfish have higher oxygen requirements than most other aquarium fishes because they are adapted to cold water (which has a higher oxygen concentration than warm water) and because they are relatively heavy-bodied, so their body mass is greater than that of other fishes the same length, and because they are messy fish that tend to foul their own water pretty fast.
And finally, yes, of course fish can go blind (except for the few eyeless species, which are, of course, already blind), but that's an entirely different problem from dying of overcrowding and polluted water.
Posted by Big Gary, aquarist  on  Wed Feb 01, 2006  at  05:13 PM
P.S.: Bazza: "This guy who works in an aquarium" is clearly a moron. Don't buy any more fish from him. Come to think of it, read a few books on fish care before you get any more fish.
Posted by Big Gary, aquarist  on  Wed Feb 01, 2006  at  05:15 PM
I have a fan tail goldfish named "bubbles" that has been going for a good 8 years now. I didnt know they could live decades though! For not knowing what sex it is I just call it a "he" for purpose of identifying with him.

I had him in 10 gallons at my old place, but had to leave him behind with my parents when I moved. Now I have a set up at work for him, when I went to rescue him... a rescue it was indeed! Parents had let the water in the tank evaporate down to a few inches (hard crusty lime all over the place.. )

Anyway to get to the point.. I think he can see quite well.. Bubbles has learned to "Beg" for his meals, by "dancing" around at the front of the tank whenever I present myself (of course he may be feeling the vibrations of movement.. but it sure looks like he can see me). I have come to the conclusion from owning him that goldfish arent as dumb as they are thought to be.
Posted by Emi  on  Sun Feb 05, 2006  at  11:52 PM
What amounts to a space suit for fish has now been invented. Enabling fish to wander around on terra firma. You could be required to take your FISH for a walk someday in the distant future...

By the way, Goldfish grow in proportion to the size of the tank they are raised in. They stay small if left in a small tank. If given some aquatic plant material, the oxygen level and water pollution can be regulated some. Theoritically, if there is the right temperature, plant material and light level and air bubble and tank size, they could live in a airtight container.
Posted by Gary  on  Fri Jul 14, 2006  at  02:30 PM
Yeah, he grows to the size of his bowl because it stunts his growth and shortens his lifespan. We are talking about VERTEBRATES here, not bosai trees. A fish that could live decades is reduced to living for weeks, if that.
Posted by Laura  on  Sun Jul 16, 2006  at  01:17 AM

I love cold water fish,I am very new to this but I have done my outmost best to take care of them,some of my"babies" have died,and it really saddens me as I have changed water on a regular basis,besides the fact that I have been told that they are the most reasonable pets to keep,I have found myself spending quite a lot more than I expected to take care of the fish,I do not mind the spending as long as they are alive and I have friends to talk to at home..I just love them,but since the few that I had just died on me,after everything I did to keep them safe,I am left with one,but I have just realised that one of his/her eyes is completely shut..what can I do? I am scared my fish will die,I want to go get more but I really am affected by the dying...the fish still plays around but I really wonder,what if the one eye is blind....? I wanted to go get him some friends but am afraid he could infect them and they will die...I use special medication(Aquarium pills) to keep the water safe but it does not seem to be doing much..Any advice for me?
Posted by Busisiwe  on  Wed Aug 16, 2006  at  10:57 AM
I'm sorry about your losses Busisiwe. What kind of fish is he? I'm assuming he's a goldfish, since you posted your question on this thread. I don't think a fish's eye can "shut" exactly, since they don't have eyelids. Perhaps something is growing on it? Maybe he lost his eye somehow? As long as he's still active and eating, that's a good sign.

If you want, we can correspond by email so as not to clog up the board. My email is .(JavaScript must be enabled to view this email address)

Here's a website you can go to, in the meantime. Good luck, I hope your baby gets better.

This may be of some use as well
Posted by Laura  on  Thu Aug 17, 2006  at  01:21 AM
I can't believe all the ignorance I'm seeing's only a fish....not all dogs need walks....pathetic.

Look, it's simple. It doesn't matter what kind of creature it is. The only question to be asked is, does it have the capability to suffer? Doesn't take a rocket scientist to figure it out.
Posted by Appalled  on  Sat Dec 09, 2006  at  11:57 AM
Amen to that! Since when did we need scientists to tell us what can feel and what can't? Just spend some time with any animal without your preconsived notions and you'll see things you never saw before. That is if you can take your blinders off.
Posted by Laura  on  Sun Dec 10, 2006  at  01:13 PM
A science fair question, 14 fish in one 2 and one half gallon tannk, 4 in another, will the four fish grow faster than the others? (small comet goldfish 4cm-8cm)
Posted by abby  on  Tue Feb 27, 2007  at  03:01 PM
please answer as soon as posible
Posted by abby  on  Tue Feb 27, 2007  at  03:33 PM
If fish bowls should be banned, then so should ALL aquariums, regardless of size! BTW some breeds of fish are suited for bowls, such as white cloud minnows, ghost shrimp, mystery snails, dwarf african frogs and bettas.
Posted by Sam  on  Tue Jan 27, 2009  at  05:14 PM
Well I was just wondering - I know that fish can suffer, but dont they have a memory span of about 5 seconds?
Posted by Camilla  on  Tue Jul 21, 2009  at  12:16 PM
I recently came across your blog and have been reading along. I don't know what to say except that I have enjoyed reading. Nice blog.I will keep visiting this blog very often.
Posted by koi fish care in  on  Sun Nov 22, 2009  at  07:03 PM
Fish are just as important as any other animal and deserve proper care.
Posted by Mary  on  Thu Mar 18, 2010  at  06:27 PM
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