Hi and welcome to the forum
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The reason why they are gasping is either;
a. They are simply suffocating in the bowl due to lack of filtration and oxygen.
b. The water quality problems (which will be very bad in a bowl) are killing them, ammonia and nitrite levels will be high, these toxins are lethal to fish and have a similar effect on fish as what carbon monoxide has to us.
c. They have parasites like gill flukes affecting the gills, mostly likely brought on by the stressful conditions of the bowl.
Or all of the above.
Basically, keeping goldfish in bowls is basically giving the fish a death sentence- there is no way a goldfish can live out its natural life expectancy (around 20-30 years or more for common goldfish) or grow normally or be in good health when kept in a bowl. Common goldfish can easily grow to over 12inches long given the right conditions, so a bowl is no place for such a large growing fish. The only fish which can be happily kept in unfiltered tanks/bowls of 1gallon or more is a betta/siamese fighting fish (although personally, i would go for a 2gallon minimum tank at least)
Fish pee and poop ammonia, this toxic to all aquatic life. There is a beneficial sort of bacteria that can break ammonia down into nitrites (toxic, but less harmful than ammonia) and then into nitrates (generally harmless, unless in excessive levels), but to survive and thrive this bacteria needs a constant source of ammonia (usually provided by the fish) and oxygen and flowing water to deliver the oxygen and ammonia to the bacteria and surfaces for the bacteria to grow on- this is provided by a filter. In an unfiltered bowl this bacteria cannot survive and so ammonia (and often nitrites) just build up and eventually kill the fish sooner or later.
The process of the bacteria converting the ammonia into nitrites into nitrates is called the Nitrogen Cycle, and the process of establishing the bacteria in the tank is called Cycling, to learn more on water quality and creating a good environment for your fish to live in, see this article in the link below;
http
/www.fishforums.net/index.php?showtopic=10099
A 30litre tank with filtration would be better for the goldfish, but ultimately is really far too small for common goldfish. For keeping common goldfish considering they can grow to over 1ft long, i would advise a 75gallon long tank minimum for a pair- although goldfish are often as tough as old boots, they need space like any other large growing fish. People often keep these fish in ponds of at least 3ft depth as they make ideal large growing coldwater fish.
A 30-40gallon tank would last the goldfish quite a while before needing to be upgraded, but you would eventually need to get at least a 75gallon long tank. If you cannot get them a much larger tank, i would rehome them now to someone else who can look after them, but if you can get them a much larger tank very soon you will need to do a 100% water change with dechlorinator once a day to help keep the goldfish going until you do get a larger tank.
Petshops will sometimes tell you myths like "if you keep a large growing fish in a small tank it will grow to fit the size of the tank well", but in reality this is just stunted growth the fish is experiencing, caused by water quality problems and not enough space to grow and excercise, in reality it is not a nice thing to put fish through as it almost always kills them before their time and seriously increases the chances of the fish suffering bad health problems. Some fish like certain types of catfish will not even experience stunted growth when kept in tanks far too small for them and just keep on growing until the tank kills them...So basically its very important to provide your fish with enough space to grow and live happily in, afterall, they are like any other animal and thrive and enjoy being provided with a good environment to grow up in
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Personally i think goldfish bowls should be completely banned, a petshop will not sell goldfish bowls if it is any good just as a good petshop will not sell cages for kittens to live permanently in- you can change your goldfishs fate now though if you act quickly as they sound like they are in a bad way with the gasping and all.
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