Care for New Fish, Swimming Problem, Why my fish died suddenly?


For "General Care"...please refer to I. through VIII.

For "Swimming Problem"...please refer to A to E.

​For "Why my fish died suddenly?...please refer to the last section.

l. Acclimation

1. After opening the box, put the whole plastic bag (without opening the bag) into your quarantine tank as soon as possible.

2. Let the bag sets for about 15-20 minutes (or longer if the temperatures in the bag and the tank water are of big difference). Once the 2 temperatures are equalized, then opening up the bag and slowly add water (about the same equal amount of water as in the bag) from your tank into the bag.

3. Let it sets for 5-10 minutes. If necessary, add an air stone into the bag water if the fish is gasping for air. Normally, the air stone is not necessary as there should be enough air in the bag water. If an air stone is added make sure the air bubbles are not too strong as to stress out the fish.

 4. Use your hand or a soft net to scoop out the fish and put them into the quarantine tank.

 5. Don’t put any of the water from the bag into the quarantine tank.

ll. Quarantine Tank

We all know live animals or fish, just like humans, have bacteria or parasites of one kind or others. And we will do the best we can to ensure the fish are free of bacteria or parasites but still animals and fish are exposing to these all the time and that is why everyone knows and practices the procedure we call… “quarantine”…This is to isolate the new fish…to put them under observation…preventing outbreak of diseases and for easy treatment if necessary…and the primarily purpose is to limit losses.

The quarantine tank should be set up with well established tank water that is water from your main or displace tank. Never use water directly from your faucet or new water.

90% of the new fish died in quarantine in the first few weeks (1st to 4th week) the fish is most vulnerable during this period... The new arrival is weak (after a stressful trip)… the new tank (not cycled) is going through its cycling…the ammonia, nitrate, nitrite levels are going up maybe reaching their highest peaks…any of these will kill the fish or make the fish defenseless against outbreak of diseases….

This is the main reason that fish die in quarantine....If you want to quarantine a new fish. Please put it in a well established tank (that is a fully cycled tank).

NEVER, NEVER use feeder fish that you bought from your local pet stores to cycle your quarantine tank. They might be the cheaper fish that you can get but they harbored a lot of harmful bacteria and parasites. Those that died from infections already ended up in the trash can in the local pets stores. Those survivers that you bought didn't die because they were already immunized or they had built up their resistant to the harmful bacteria or parasites. But once the new fish are introduced to the quarantine tank with the feeder fish the stress and weak new fish would be prone to attack by the bacteria or parasites which were carried by the feeder fish.

Even if you took out all the original feeder fish before putting the new fish in it would not guarantee that the water in the tank is free of harmful bacteria or parasites as they might be harbored in the filter or in the airstone....

III. Salt

Add about one teaspoon of non-iodine salt per gallon into the tank water after you have the fish in. Let the salt dissolve slowly. Never add salt before putting the fish into the water.

IV. Medications

Don’t add any medications in the first few days. Just observe them and add medications only when it is necessary and accordingly.

In the first few days the fish may be very stress and without any resistance adding strong medication will kill them.

​It is also very IMPORTANT​​​ not to use "Stress Coat" on the first day of arrival. "Stress Coat" is a sligtly thick and slimy liquid which gives a coat over the fish body to protect ​the fish. But it might be harmful to a newly arrived fish as the "Stress Coat" might cover and block the very fragile gill blood vessels of the fish and making the fish have problem of breathing (when it is most needed) and the fish might die of suffocation. You can use "Stress Coat", if necessary, the next day when the fish has settled in its new environment.

 V. Food

No food for the first few days. As the new fish might be very stress and will not show any interest in food and might not even recognize what you put in for them is food.

This might even be the first time that they are being placed in a glass tank. Before their arrival they might have been kept in a pond all alone. Now they have to deal with a new environment…. in a glass tank.

Don’t panic if the fish don’t eat for days. They will eat eventually when they are hungry. They will not die without food for a few days. But they will die with uneaten food left in the tank unattended.

VI. Recuperate

Create a peaceful and quiet environment for them so they can recover from a very stressful trip.

      (1)Turn off the over head lights.

      (2) Lower the air bubbler so as not to create an irritation for the fish.

      (3) Raise the water temperature to 75- 80 degree. In a normal condition, goldfish don’t need a heater.

      (4) Don’t keep approaching the tank unless it is necessary.


VII. Sitting or Floating

Sitting around… not active…bouncing at the bottom…floating up-side-down…these are all normal for new arrivals because they have gone through a long and stressful trip. The box they were in might have been bumped and tossed around many times. They are acting up… not moving much…floating… because they are trying to conserve their energy by not controlling the muscles to maintain their buoyancy.

Do the things listed in VI above will low their stress level and help the fish to recuperate and settle in a new environment.

VIII. White fuzzy stuff on the head

Sometimes (specially in winter) you might see some white fuzzy spots on the head growth of the fish (specially Orandas or Ranchus). These are normal... they are fatty tissues (or protein) that the fish stored in their body before winter so they can be in a hibernated stage without eating during winter and when spring comes they will ooze out of its body in a white milky form.

If you turn the heater higher they will go away faster. Or you can use a cotton bud or Q-tip to wipe them off. But actually it is not necessary to do anything as they will eventually go away.



A major problem with goldfish is that they might have swimming problem… like floating or swimming sideway. These can be caused by various factors :-

A. Stress

A new arrival fish is stress after a long rough shipping trip…or an old fish is stress due to bad water quality…these can cause the fish to have swimming problem. Giving it time to settle will normally overcome the first situation as outlined in VI. "Recuperate" above….Regular water change will help reducing problem as the latter. Avoid using flake food as goldfish are big eaters and by the time you put enough food in there for them more than half of it will melt and drift everywhere and being sucked into the filter. This will mess up the water quality eventually.

B. Constipation

Sometime a goldfish can eat too much and become constipated and lose its buoyancy… giving the fish a lot of veggies and fasting them (please see also D. below) can help to clean their internal system.

C. Soak the fish food

If you are feeding your goldfish with pellets please remember to soak them before you give the food to the fish. As goldfish gobble up their food very fast and if they take in the dry pellets too fast the dry pellets will slowly expend inside their body and injure its internal system and causing swimming problem…this is a common sight after feeding…that is acting up after eating and back to normal the next day….

D. Obesity

Nowadays, fish foods contain too much nutrients and too much food will make them obese. The building up of too much fatty tissue inside their body will block up or take up space for the swimming bladder to inflate or deflate in controlling their buoyancy….Don’t spend high dollars in buying so call premium fish food…Cutting down in feeding…once a day will be more than enough…goldfish will not die of hunger but they die because of over feeding…Again feeding them with a lot of veggies and fast them from time to time so they can slim down. Every one or two months stop feeding 3-4 days straight. This practice can be done when you are on a short vacation or short break.

Too much good food will only cause the body of the fish to grow fast but its fins are not catching up…. It has a too heavy body to carry without the right proportion of fins to balance its swimming.

E. Too much air bubbles

A lot of tanks have turn up their air pumps to the max which will give out too many bubbles… these will irritate the fish and stress them or they will take in too much air into their system …causing lose of balance….


(1) Don't m​ake your own food..​.a lot of time the ingredients that you bought (even from well known suppliers...some they say with antibiotic) are contaminated and full of bacteria...that is why some fish suddenly die without apparent reasons. Bacterial infection is also the main cause for dropsy to a fish...bacterial  infection to the kidney...when the kidney of the goldfish does not function properly... it retains too much water in its body which becomes swollen and makes the scale stand up like pine-cone.

(2)  Don’t use flakesgoldfish are big eater and you have to put a large amount of flakes into the tank to feed them. By the time the fish can get to all of them… they drift …they melt…they got sucked into the filter…they got trapped in dead areas where there are no current…all these will mess up the water.

(3) Give them floating if there are any left overs you can always scoop them out... Soak them before feeding. From time to time give them frozen blood worms and a lot of green veggies and carrots (boil and soften them).

Don't keep plecos in your tank...but if you must then just keep a small one to clean up your algae. As pleco will go after the slim coat on the body of the goldfish when they are hunger...especially at night when the goldfish are not active. The slim coat is the first defense from sickness for goldfish.



Fish are just like human, we carry all kind of germs and bacteria all the time. But we don’t get sick when we are strong and our immune system is high. But once we are stress then we get sick because our immune system is low. Fish are the same, their immune system is down and bad bacteria start attacking them…this might be due to (a) poor water quality, (b) the food that we giving them, and (c) introducing a new fish that has infectious bacteria….

 So the only ways to prevent the bacteria issue are :

(a)   Making sure that water quality is good…which includes checking the pH, ammonia and other water perimeter …these play a very important role …The next most important thing to improve the water quality is ….regular water change…this is just like replenish some fresh air into a smoking area  and I don’t need to stress how important it is here… But would like to say that when people started the hobby they would have very consistent water change (every week, every month) …but after a while they become slack…. And keep saying to themselves…I’m too busy today and the fish look OK. I will do it tomorrow or next week…but by the time the fish look acting up then it is too late…So he starts doing a 70 or 90% (normal water change is 20-25%) change...this is how he would kill all the fish in the tank instantly due to temperature shock or pH shock…. or it is too late to do water change now because the fish are all poisoned by the chemicals in the water…. All their gills were burned by the acidic water….

(b)   The food we are giving to the fish…a lot people are making their own fish food. They buy the ingredients from some suppliers who branded what they are selling contains anti-biotic and other healthy ingredients which might all be bogus.   

 And then in the process of mixing/preparing the ingredients the food is contaminated by bacteria…Please refer to "Don't make your own food" paragraph (1) in   FEEDING IN GENERAL above.

(c)   Introducing a new fish that has infectious bacteria…this is self-explanatory …and that is why we need to quarantine the new fish when we buy from a source that we do not trust....(For setting up a quarantine tank...please refer to paragraph II above "Quarantine Tank".