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Joan, Vet Technician
Category: Pet
Satisfied Customers: 17304
Experience:  Vet Tech for 35+yrs. Small Animals and Fish
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goldfish open mouth, other fish not experiencing same stress.

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goldfish open mouth, other fish not experiencing same stress. help!


My name is XXXXX XXXXX I am a Vet Tech for 30+ youyears and have kept fish for over 40+ years.

Can you tell me the size of the tank?

How many fish are in the tank?

Type of filtration?

Did you check the Ammonia, Nitrites and Nitrates?

What type of test kit are you using?

Why are you using an antibiotic?


Customer: replied 3 years ago.

15 gal tank, two goldfish, small, not fancy. Filter for 30 gal. Not sure of brand of test kit, water was new 6 days ago. Aeration. Only one fish sick. Used "General Cure" because I suspected flukes three days ago. Open mouth is new in past two days. Sick fish isolated in tank but still in same tank (no hospital tank set up). Other fish will bully sick fish. Fish appears to be eating at times, not normally though. Haven't tried aquarium salt.


I'm new to goldfish but have kept tropicals for years, my Bettas typically live 4+ years.


Is the fish bloated at all?

Is he staying at the top of the tank?

How long has the tank been set up?

What was the ammonia, nitrites and nitrates?

Did you do a dip stick test or a complete test?


Customer: replied 3 years ago.

Fish not bloated. Tank is new, but cycled. Added additional bacteria when added fish as well. Tank has had fish in it for a week. I don't think this is an ammonia/nitrate problem, as the other fish isn't stressed in the least.


He was able to swim normally but was somewhat lethargic a few days ago when I isolated him. Swim bladder seems fine, he will periodically swim up/down and can extend all fins and move sideways but is lethargic and doesn't choose to swim around unless "need" is there, like the mini-tank is moved or the other fish surprises him. He is able to control his position if I move the mini-tank to feed (it's floating.)


Sorry I need to get more information to be able to adequately assist you.

Can you tell me what product you used to cycle the tank?

How long has the tank been running?

Can you do a water parameter test now and give me the readings?


Customer: replied 3 years ago.
I cannot do a reading now as I am not near the tank. I used Cycle on the tank. It has been running for just over a week.


I suspect the problem is with the water parameters. The best products to help cycle a tank is Fritzyme #7 or Bio Spira. These are nitrifying bacteria that help cycle the tank faster. A tank even with the best products will not cycle in a weeks time and does need the water parameters checked on a regular basis. The Ammonia should be 0, Nitrites 0 and Nitrates 20ppm or less. The strip type tests are inaccurate and you should use a test kit like the API master test kit. They are pricey, but work well.

What I would like to try is a 75% water change today. Do not add any medications, since that can drive up the water parmeters. Add one teaspoon full of aquarium salt per gallon of water this one time in the water you add to the tank. I suggest using bottle spring water for the change, since it has the ammonia and chloramines already removed. You will need to monitor the water parmeters and each day do a 25% water change. If the water parameters go up, them you can do a 35%-50% change, but do not change the whole tank, since that will start the cycling over again. The salt acts as a tonic and kiis parasite, fungal infections, bacterial infections and reduces stress. It sounds like the one fish is more sensitive to water quality, which we see all the time and the tank is going through new tank syndrome:, so this problem is not uncommon. Please try this and let me know how the fish is doing after the water change and the aquarium salt treatment. If you can get some Fritzyme #7 or bio spira that would help greatly to help cycle the tank. It will still take about 3-4 weeks to complete the cycling. Joan

Joan and other Pet Specialists are ready to help you

Hi L,

I'm just following up on our conversation about your Gold Fish. How is everything going?


Customer: replied 3 years ago.
Hi Joan,

Adding more bacteria and salt and changing out the water did little if anything to help the fish, whose mouth is still open (cannot eat) and who
Is breathing/moving at the same rate but of course growing weaker before our eyes as she cannot eat. We have continued to isolate her as she is quite fragile.

We were advised by others check of foreign bodies in her mouth, and did not see any.

Thank you for checking. We continue to hope that we may be able to provide her with care, as she is clearly suffering.



I am going to give you a link to contact some Fish Vets. That may be the only option to try and help her. This link can locate a Fish Vet in your area. You out in Ornamental fish. the state you live in and USA and it should bring some Fish Vets up. They may better be able to diagnose and save your Goldfish : .We are limited to what we can do being online, since we cannot see the fish and examine them. Joan

Customer: replied 3 years ago.

Hello Joan,


The fish died this morning.


Thank you again for your help.