Though some Goldfish breeds are delecate, Common goldfish are actually very hardy which is why they make such good pets. They can survive in outdoor ponds (even at tempratures which freeze the surface) and will eat almost anything.
However goldfish are also far messier than tropical fish, and produce a lot more waste. They only have an intestinal tract, without a stomach. So they cant digest excess proteins, and instead excreet it back into the water. This is a problem that needs to be addressed either with heavy filtering, frequent water changes, or both. If this is not done, they will eventually pollute their own water to the point where it is toxic, and they will die.
Water Quality
In general, water should be clear. But it is not an absolute indicator of how good the water is for your fish. Cloudy water can still be fine, and crystal clear water can still be toxic.
Water Changes
Water changes are never bad for your fish. You can do them every day. But with proper filtration (and assuming your tank isnt overpopulated), you can reduce the frequency of water changes to once or twice a month. Changing 20% to 50% of the water volume is good. Changing the water will instantly oxygenate the tank and will instantly remove pollutants such as ammonia.
Do not forget to use water conditioner on the new water, and if you use aquarium salt, that will need to be (proportionally) replenished as well. You should make an effort to make sure the water is the same approximate temperature as the water in your tank to avoid stressing the fish.
Temperature
Goldfish are coldwater fish, but are healthier in a heated tank. The ideal temprature of the tank should be in the 68F to 75F degree range, but they can tolerate temperatures from as low as the 30s to as high as the 80s.
Warmer water holds less oxygen, so fewer fish should be kept in warm tanks (or additional effort taken to increase oxygen, such as surface agitation or airstones). They can tolerate temperatures to around 90 degrees....any hotter than that and you will need to cool down the water or they will die. I have used a couple small pieces of ice in the power filter, but you could also accomplish this with a water change using cold water.
If you live in a cold area, you can buy a heater for your tank to maintain a warmer temerature. But in most areas, indoor room temperatures are probably sufficient to maintain their ideal range. Common goldfish can also tolerate near-freezing water (32 degrees). Common goldfish can even weather periods where ponds are frozen over, so long as they have enough oxygen and food. But fancy varieties are probably too delicate for such cold water.
Temperature changes should be gradual so as not to stress the fish. All tanks should have a thermometer so you can track the temperature. Most pet stores sell adhesive strips that you can stick on the outside of the tank that are very cheap (under $2) and unobtrusive.
New fish should be acclimated to the water temperature before putting them into the tank. Float the bag on the surface of the water for 15 or 20 mintues before putting them into the tank. Dumping a new fish into the tank will stress it and increase the possibility of illness or death.
Keep in mind that a stable temperature will discourage breeding behavior. So if you want to breed them, you need to mimic conditions in nature; starting from a cold period and gradually warming. See the breeding section for more information. Back to Top
What is pH?
pH measures how acidic your water is. A pH of 7 is considered neutral and is ideal for goldfish. Above 7 is considered alkaline (aka "Hard Water"). Below 7 is considered acidic (aka "Soft Water").
The pH scale is logarithmic...so a pH of 5.5 is ten times as acidic as a pH of 6.5. This is important in that the more radically the pH changes, the more it will stress your fish. If the pH changes by more than 0.3 per day, it will stress your fish. The "normal" range for most fish is between 6.5 and 7.5.
Water can be "Hardened" (made more alkaline) or "Softend" (made more acidic) by way of chemicals that you can buy at most pet stores. Read the instructions and be very careful when altering your water pH.
Carbon Dioxied and high water temperatures will tend to make water more acidic (lower the pH). Oxygenated water will tend to be higher pH.
Be aware that the importance of pH is often exaggerated. A stable pH is more important that maintaining it in the ideal range for Goldfish. The process of altering the pH of your tank is likely to stress the fish more than the fact that it is not in the ideal range. The general consensus seems to be that altering the ph of your water is more toruble than it is worth. So you should only alter the ph if it is absolutely necessary.
Aquarium Salt
Aquarium Salt comes in
cartons like this
In nature, Freshwater is not the same as what comes out of your
tap. Tap water is truely salt free, but most freshwater is not. So a "freshwater"
tank can contain small amounts of salt and still be fresh water.
Goldfish dont absolutely require salt in their water, but it does enhance their immune systems by stimulating them to produce more mucus over their scales. Goldfish are supposed to be slimy. This is normal and desirable. Salt will enhance gill function (allowing fish to absorb oxygen a little better) and reduces the rate of nitrite buildup in the tank.
n addition, salt is toxic to many parasites that infect goldfish (including Ick, the most common parasite). So a salt environment will augment their immune systems in this way as well. Higher concentrations of salt are used as "salt baths" to immerse sick fish in for short periods.
Salt tolerance of other fish
Goldfish can tolerate low levels of salt. Almost all freshwater fish can tolerate salt to some degree. But be aware that some freshwater fish do not tolerate salt well at all, so make sure you dont have any of these fish in your tank and do not plan on adding them. They include tetras, catfish (including plecos), loaches, and any scaleless freshwater fish (though the consensus seems to be that you shouldnt mix goldfish with tropical fish anyway, salt or no salt). Snails are also not crazy about salt water, but some freshwater snails can endure the amounts you will use in a goldfish tank.
Be sure to use only Aquarium salt
Do not use iodized table salt. Table salt has Iodine, which is poisonous to fish. You can use Kosher salt but its best to remove all doubt and just use aquarium salt from a pet store. Always fully dissolve salt before adding it to the tank. Undissolved salt can chemically burn your fish.
The normal amount of salt for a freshwater aquarium is one rounded tablespoon per five gallons of water volume (there are three teaspoons in a tablespoon, and two table spoons equals one ounce). But follow the directions on the box. To avoid stressing your fish, add the recommended amount of salt slowly (1/4 normal amount per day for four days).
A low concentration of salt is 0.1% (1 teaspoon per gallon). A medium concentration is between 0.1% and 0.5% (5 teaspoons per gallon). A high concentration is 0.9% (9 teaspoons per gallon) or above.
High concentrations should only be used for very short term treatment for sickness. Medium concentrations are dangerous in the long term and could kill your live plants as well. 0.3% is the maximum amount of salt that is safe for goldfish in the long term.
Keep track of salt collected in your tank
You must keep track of how much salt is in your aquarium. The only way to remove salt is through water changes. Salt should be fully dissovled before being added to the tank. Direct contact with undissolved salt can chemically burn your fish.
Regarding evaporation
To avoid accidentally putting too much salt in your aquarium, make sure you top the water in your tank BEFORE you do water changes. Replace salt in the new water proportionally before putting it into the tank. Once the fish are already acclimated to salt water, you dont have to worry about putting it in slowly anymore.
Salt has a lot of advantages, but you have to pay attention when using it. If you do lose track of how much salt is in your aquarium, the safest course of action is to start over. Do three 50% water changes over the course of a week (adding no salt), and then begin adding salt slowly as if it is a new tank. Back to Top
Biological Filtration
This referrs to the bacteria that naturally live in your aquarium. You dont have to put these in; they come in your fish and populate your tank by themselves. They exist pretty much everywhere in nature except in your tap water (because it is chlorinated).
The function of these bacteria in your aquarium is to neutralize waste products in the water produced by the fish, thereby reducing the overall frequency of water changes. Your biological filter will not remove the need for water changes completely however.
Nitrification (Aka "Biological Cycle" aka "Start up cycle" aka "Nitrogen Cycle") is the process by which beneficial colonies of bacteria establish themselves in a new tank. They come with your fish (so the process cannot start until you actually put fish in the tank), but it takes a period of time before they can replicate themselves sufficiently to function as a filter. You'll never actually see them...they are very small. But they are there.
It is possible to cycle a tank without using any fish (by way of adding ammonia yourself) but the process is involved and complicated. Pet stores sell what amounts to fully sycled water in order to "jump start" the process. But the best method is probably to use living fish and plants.
Do not be fooled by crystal clear water; the fact that your tank looks clean does not mean it is not toxic to the fish. Unlike a lake or a river, an aquarium is a closed system. Waste products produced by your fish and from decaying food in the tank remain in the tank unless they are removed or neutralized.
This can be accomplished by frequent (daily) water changes, but for most people this is impractical. The alternative is a biological filter; using plants or colonies of benign bacteria to convert the waste for you, so you dont have to change the water as often.
Ammonia
When urine and feces decompose in the tank, ammonia is released. There are two types of ammonia, but only one is dangerous to fish. When talking about ammonia levels, this is the type of ammonia that is a concern. Any amount above 0ppm is toxic, but levels at 2ppm (Part Per Million) or more is dangerous. Ammonia levels typically begin rising the 3rd day after fish are introduced to the tank.
An Ammonia Test Kit
If you want to remove all doubt, you can buy a monitor strip from any pet store. These look similar to thermometors that suction-cup to the inside of your tank. They provide a real-time measure of how much ammonia is in the water at any given time. They work continuously, but need to be replaced every one or two months. They typically cost between $6 and $10 if you buy them individually. Pet stores also sell kits with replacement strips that will average out much cheaper.
Nitrosomonas
These are the first type of bacteria that live in the tank. They eat ammonia, but excrete Nitrites, which are also toxic to fish. Nitrite levels begin rising the first week after fish are introduced.
Nitrobacter
This is the second type of bacteria that live in your tank. They eat Nitrites and spit out Nitrates. Nitrates are also toxic to fish but to a lesser degree, and are harmless at low or moderate levels.
So the point of the biological filter is to convert substances which are very toxic to your fish into substances which are only mildly toxic. Water changes still need to be done to remove nitrates once they get too high, but because your fish have a much higher tolerance for them, water changes can be farther between. Live plants can further augment your biological filter, but have potential problems of their own (see the plant section Setup and Maintanence for more info)
Kits to test for these chemicals are available at any pet store. The cycle is fully established between 2 and 6 weeks after the fish are first intruduced. The bacteria grow more slowly in cold water. So warmer water will accelerate the cycle.
A note on changing your filter media
The filter media in your power filter (if you have one) is where most of the bacteria live. When you throw this away, you killing off the bacteria, and they have to start over with the new media. When changing your filter media, keep in mind that your biological filter will be weakened until it can re-establish itself. For this reason, many commercial filters use separate media...one on which the bacteria grow (which is never changed) and one which is disposable and can be periodically replaced. Back to Top
About Snails
An Apple snail
Aside from their asthetic value, snails
eat one of the true pests of an aquarium; algea. And they are better at it
than anything else you can put in your tank. That being said, moderate to
high levels of algea will still reproduce faster than the snails can eat them,
and you will still need to scape them off occasionally. They do eat live plants
as well, but not to a great degree. Any live plants that can withstand the
constant pecking of goldfish will probably endure snails as well.
Most freshwater aquarium snails are from the species Marisa Cornuarietis (part of the family Ampullariidae...aka "Apple Snails"). Like goldfish, these have been bred into a variety of shapes and colors, but they are all the same species. Marisa Cornuarietis are not asexual, unlike some snails. So if you want them to reproduce, you'll need at least two.
Their reproductive process involves laying a clutch of eggs outside the water (so they will need several inches of space above the water line). Their eggs vary from pale to bright orange and look vaguely like a teaspoon full of tapioca pudding clinging to the glass. They gestate in about a month. The eggs need to stay moist but cannot be submerged, or the young will drown.
A Black Mystery Snail
The other type of snail common to freshwater aquariums is the pond snail. These are asexual, and a single one of them can quickly pollute your tank with dozens more just like it. They are generally undesirable because they are so small; they are not asthetically pleasing and dont eat algea very well. They tend not to last long in goldfish tanks though, because goldfish will eagarly east them. For this reason, a log of petstores will put a goldfish in with their tropical fish to eat any pond snails that are in the tank.
Other snails should get along with most goldfish fine, although the goldfish may nip at them. For this reason you should keep snails that are big enough that they can weather this behavior (if they are about the size of the largest fish's head or larger, they should do fine). They should be able to survive in any environment that goldfish can survive in. The general consensus seems to be that aquarium salt is bad for snails, but they can endure the low concentrations found in freshwater tanks. Back to Top
Feeding Goldfish
Goldfish are omnivores, and will eat anything they can fit into their mouths. They originated as bottom feeders (similar to catfish) and prefer foods that sink to the bottom or float in the middle, but can eat common flake food on a daily basis. The only reason floating foods arent great for them is because it forces them to swallow air while feeding.
Most owners feed them live (or freeze dried) food such as blood worms or brine shrimp once a week as a supplement. These are very good for the fish because they are high in protien, but will cause digestive problems if given every day. Goldfish will be very happy to eat the live versions of these foods, but freeze dried versions remove the possibility of parasites. Live food sold at most pet stores is unlikely to have parasites, but with freeze dried foods the chances are almost zero.
Despite the fact that it floats, the best food for goldfish are the pellets sold for Koi (Hikari is a good brand...pretty much anything with asian writing on it is probably a good bet). In fact, Hikari makes a brand specifically for goldfish. These foods are designed to enhance the colors of the fish as well as provide good nutrition and will not cloud the water like flake food will. Just make sure the pellets are small enough that the fish can swallow them.
Goldfish are gluttons...they will literally eat until they explode. They will eat even when they are no longer hungry. Feeding them too much will eventually cause their intestinal tracts to rupture and they will die. So you have to be careful in how much they are fed, especially for smaller fish.
Feed them as much as they can consume in a 5 minute period, and only feed them twice a day. Keep the high-protein foods (like blood worms and shrimp) as a once or twice a week treat to augment their normal diet of flakes or pellets.
A sign of overfeeding is a line of feces trailing from their cloaca. It is always better to underfeed than to over feed. Aside from the fact that it may damage their digestive systems, it also produces more waste, which in turn pollutes the water as it decomposes into ammonia. The result of this is that you will have to change the water more often (See Biological Filtration for more info). There is anecdotal evidence that goldfish will actually live longer if underfed.
The amount of protein they consume (flake food, blood worms, brine shrimp, pellets, ect..) should be limited when possible. High protein foods stress their digestive systems. Small amounts of flake food (less than a mouthful per fish) are ok once a day. Pellets are better for them however. You can be more liberal feeding them fruits and vegetables. Since they contain less protein, they wont stress the fishs' digestive systems as much.
Yes, Goldfish can eat raw fruits and vegetables. The food should be cut small enough that they can eat it, though they can tear off pieces of more supple foods (like oranges). A lot of people put cut slickes in the tank. The fish will graze on it like cattle. Typical foods include oranges (the vitamin C boosts their immune system), skinless peas, and lettuce. Cut it in sections that are small enough that they can either swallow it whole or bite off chunks of it. Oranges (or other fruits containing citiric acid) should not significantly alter the water chemistry, but excess food should be removed from the tank once they are done feeding.
Goldfish can be tamed to the point where you can feed them by hand, as shown in this video. Back to Top
Sickness
Sickness is most often caused by stress. All fish endure a low level of infection constantly, but their immune systems can keep it in check so long as they are healthy. When you handle the fish or when they are scared it will cause stress, and weaken their immune system, which will allow the infections they already have to become stronger. Other factors are parasites and bacteria introduced through new fish or live food, injuries, and dirty or contaminated water.
Maintaining good water quality is the best method of prevention, and the best way to help the fish's immune system recover. Adding aquarium salt to the tank will enhance their mucus layer and improve the function of their immune system. Salt is also toxic to most parasites.
Do NOT pet your goldfish. Many goldfish can become very tame, and some even seem to crave this kind of attention. But petting them rubs off the mucus layer that covers their scales and protects them from parasites and bacteria. Fish are not puppies.
Most diseases can be cured using broad-spectrum anti-biotics from a pet store in conjunction with salt. Remember to remove carbon filters when medicating, as they will filter the medication from the water.
Ick
This Chocolate Oranda is
infected with Ick
This is a parasite that looks like tiny white dots on the surface of the fish. It is potentially fatal if left unchecked, but easy to treat. Ick-specific medication is sold at any pet store and is cheap. This is probably the most common sickness seen in aquarium fish in general, so you should always keep some ick treatment on hand. Ick does not tolerate salt well at all, and adding aquarium salt to your tank will prevent ick infections and help to accelerate the recovery of fish that are already infected. When treated properly, ick can be cured in as little as 2 or 3 days.
Swim Bladder Disorder
Fish maintain their balance in the water by use of an organ called the swim bladder. If it is deformed or diseased, they will be unable to regulate it and keep their balance. Symptoms are the fish being unable to stay upright and level in the water. The fish may sink to the bottom of the tank or be stuck at the surface. It may even float upside down. The fish will become listless and will probably stop eating.
Many exotic goldfish suffer from this to some degree due to their body shapes. But if the fish was swimming normally before, and these symptoms appear in the space of a few days, it is probably due to disease or a dietary problem (like constipation).
The dietary problem is easy to fix; stop feeding the fish for a few days. Then feed it steamed, de-skinned, and crushed peas (which will cure constipation) until it starts swimming normally again.
High nitrate levels can cause swim bladder disorder as well, so be sure to test for Nitrates to make sure swim bladder disorder isnt simply a symptom of Nitrate poisoning.
Fin Rot
Symptoms are ragged or frayed fins. Probably the result of bacterial or fungal infection due to stress, but can also mean the water has a PH that is too high. Fin Rot starts at the outer edges and eats it's way to the base. If it reaches the base of the fin, the fish will never be able to re-grow the fin again. Treat with goldfish anti-biotics from the pet store, and fix your water's pH if necessary. Fin Rot may require multiple cycles of treatment to erradicate completely.
Dropsy
This fish died from Dropsy
Usually caused by a bacterial infection of the Kidney, the fish's body will bloat and it's scales will stand out like a pinecone. There are medications for it, but the concensus seems to be it is 95% fatal; by the time the scales stand out and the body bloats, the damage has already been done. The organs are destroyed, and even though the fish may appear to get better for a week or two, eventually the organ failure will kill it.
Unlike Ick, Dropsy is not very contagious. But the infected fish should be removed from the tank as soon as possible. Medication for Dropsy can be bought from any Aquarium specialty store. If the fish survives at all, it should fully recover with a week.
Oxygen Depravation
If the oxygen content in the water is too low, the goldfish will become lethargic, and attempt to gulp air from the surface (also known as "piping"). Eventually the fish will suffocate and die. Warm water has lower oxygen content than cooler water, so the warmer the water the more you have to pay attention. Surface agitation (bubbles) will encourage gas exchange and put more oxygen into the water. Power heads, airstones, and bubble walls will also oxygenate the water very well for the same reason.
An immediate solution to oxygen depravation is a simple water change. Thats it. Changing the water will instantly give the fish oxygen. But if it is a continual problem, it may mean you need a bigger tank (more surface area for gas exchange) or fewer fish.
Salt Baths
Most treatments will include quarantining fish in a separate smaller tank, usually with higher than normal salt concentrations (referred to as a "salt bath"). Salt will enhance the performance of many medications.
Salt baths are usually one gallon of aquarium water with 4 teaspoons of salt dissolved. Never add fish to a tank with salt that is not dissolved, as it could chemically burn the fish. Fish should be immersed more than 5 minutes, but no more than 30 minutes.
Salt Dips
Higher concentrations of salt (up to half a cup per gallon) can be used to treat persistent parasites, but the fish should be immersed for shorter periods (between 30 seconds and five minutes). The fish should swim around normally, and may float to the top. This is normal behavior. The fish should respond by swimming again if you poke it. If it doesnt respond (or if it seems unusually distressed), take it out of the Salt Dip immediately. The fish should not remain in the dip longer than five minutes, no matter how well it appears to be handling the water. Prolonged periods of high concentrations of salt will kill goldfish.
Important note on Carbon Filters - If medicating remember to remove carbon filters. They will filter the medication out of the water. Back to Top
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