Suddenly dead goldfish

Question
QUESTION: Hello - I've had a 10 gallon tank since April 2007. (Daughter came home from fair with goldfish in a baggie - couldn't flush him, couldn't consign him to horrid bowl, so got a tank, filter, gravel, and 2 other comets for company).  The three of them have been happily co-existing and grown to the point where I was about to upgrade the tank for them.

I don't know the pH, ammonia or nitrate levels, but have quasi-faithfully done a 20% water change every week or two.  I vacuum the gravel regularly and try to keep the tank "clean enough."

Two days, one of the fish just died.  His intestines looked dark, but not overly swollen, and he seemed to have almost a white, cloudy look about his body.  The other two fish seemed a bit subdued.  One of them had a whitish look to him, and this morning, he was dead too.  

I'm fairly certain I've somehow messed up the water quality, but what do I do for the third little guy?  I'm horrified at the thought that i've killed my fish.

ANSWER: Hi Annaka;

Poor guys. I'm so sorry you lost them. Hopefully we can figure this out in time to save your last guy...

It could be something going on with the water. The first thing to do is to make a 25% water change. Add aquarium salt too, 1/2 teaspoon per gallon, 5 teaspoons total. Any uniodized pure salt with no other additives will do if you can't get to the fish store right away. Grocery stores have it for use in homemade ice cream machines.

Get the water tested at the local fish store for the presence of ammonia and nitrItes (not nitrAtes, it's different). If there is any trace of ammonia or nitrite, keep changing 25% of the water every day until they are both at "zero". Make sure the fish store tells you what the actual levels are. Don't let them tell you it's "okay" or "a little off". We need the actual numbers of the results of the tests for both toxins.

If the test results show that the ammonia and nitrite are "zero", there could be an infection going on in there. Look closely on your fish for;

Spots, dots, redness, swelling, or anything that seems unusual.
Does he have any place on him that looks fuzzy or cottony?
Does he look as if he has a "gold dust" on his body when you shine a flashlight on him?
Are his scales outlined in white or red anywhere, especially on his back?

There are many possibilities for disease and infection so let me know what you see and we can go from there. Just please do not add medication until you have the water test results. If the water isn't right, medication can make him more sick. If it turns out he needs medicine, you can also look at the fish store in the medications department. Compare your fish's symptoms to the ones listed on the packages and find something that you can treat with.

I hope he's okay...

At Your Service;
Chris Robbins

---------- FOLLOW-UP ----------

QUESTION: Hi Chris- thanks so much for your quick reply and good advice. I've added the salt and will have the water tested as soon as the fish store opens.

My remaining comet doesn't seem to have any fuzzy or cottony look to him, but I think that the two who died may have. It wasn't just "a place" on the fish, though, but rather, the entire fish seemed to have nearly a white cloud about him.  Almost like the scales were disintegrating?  Is that a preventable bacterial infection?

Thank you very much for your help - annaka

Answer
Hi Annaka;

It may have been some sort of bacterial infection, often columnaris is the culprit. The prevention for all disease is supporting the immune systems of your fish with clean water and good diet. Even a daily 25% change for a few days isn't too much, just to get the tank as clean as possible and then be sure to do a weekly 25% change with gravel vacuuming after that. It will also reduce the numbers of infectious bacteria that could be in the water.

You could treat with a fish antibiotic called "Maracyn Two" or feed an antibiotic food if you want to. (Don't do both at once) I don't normally recommend "preventive" treatment with antibiotics but in light of the loss of two fish already, you may want to do it anyway.

Once he seems okay, it would be best that he stay alone. Goldfish are very messy fish that get very large and need at least a ten gallon tank just for one. Here is a good web page about them for more info;

http://www.firsttankguide.net/goldfish.php

I hope he does okay. Followups welcome...

At Your Service;
Chris Robbins