Golden Danio Parasite

[enordquist]

Hi everyone,
 
I'm definitely an amateur compared to most of you.  I have 3 golden danios in a 2.5 gallon tank.  Even though it's not much, I've had the fish for almost 4 years and they've become important to me.
 
About 4 days ago, I noticed one of the fish wasn't eating.  Two days later, a wound appeared on its side and a thin string was coming out.  After doing some research I figured that anchor worms most matched the description, but I don't use live food and I didn't introduce any new fish or plants within the last two years, so I'm not sure if that's the right diagnosis.
 
I went and picked up some coppersafe, which is what my local aquarium store recommended.  I then attempted to remove the worm from the fish.  Instead, a big white clump came out of the wound, I am not sure what it was.  I put the fish back into the tank because it was very stressed, and I've been using tetracycline in case of infection in addition to the copper.  Within the last day, the fish has had trouble swimming.  It sinks to the bottom and takes a lot of effort to stay floating.  
 
Basically, what I need to know is:
 
Is it anchor worm? (And if so, where did it come from?)
Why is the fish having trouble swimming?
Am I treating it correctly?
Do I need to remove everything from the tank (gravel, decorations, two other fish) and clean it, or will the copper take care of that?
Should I attempt to remove any new worms that appear?
 
Because I haven't had any problems with them before, I don't measure the levels of anything in the water or do frequent water changes.  The other two fish seem fine and continue to eat.
 
 
Any help would be much appreciated, thank you.  (Sorry for the length)

 

[the_lock_man]

Without a photograph it's difficult to tell whether it's anchor worm or not.
 
THe problem you are now facing is that you ahve got two lots of medication going on in the tank at once. Coppersafe is effectively a poison - it is chelated copper. It works by calculating a dose which is lethal to the parasite, but not to the fish. Whilst it's not lethal, it is still affecting the fish, poisoning them, just not to a level at which they would die.
 
And you've got an anti-biotic - to kill off any bacterial infection. It kills bacteria. In your filter live 2 colonies of bacteria, which process the toxic ammonia produced by your fish, via nitrite, into nitrate. It could easily be that your tetracycline has killed those bacteria, and you have high ammonia or nitrite levels in your tank. Without you being able to test your water, we can't tell how badly this is the case.
 
You will also be suffering from Old Tank Syndrome, since you don't do water changes. THis is where the nitrate level in the tank builds up to unusually high levels, but the fish become accustomed to that level - then you do a water change, and reduce the level of nitrate in the tank, and this shocks the fish.
 
Without knowing ammonia, nitrite and nitrate levels, there's not much more help I can give you.

 

[enordquist]

I'm going to go buy a test kit today and I will try to get a picture for you!

 

[the_lock_man]

 

[enordquist]

So I tested the water, and I don't think the results are very good.
 
Nitrate: ~200 ppm
Nitrite: 0 ppm
Hardness: ~300 ppm
Alkalinity: between 0 ppm and 40 ppm
pH: ~6.2
Ammonia: between 0 ppm and .25 ppm
 
I know the nitrate is extremely high, but I'm not sure why.
 
I also tested the copper levels, since I'm using coppersafe, and they were low, between .25 and .5 ppm (since coppersafe is chelated, it should be between 1.5 ppm and 2 ppm right?)
 
 
On the brighter side, the fish ate a little bit this morning. And is still alive.
 
Here are pictures, sorry about the blurriness.  The first picture is from the first day I noticed it, and the second picture is from this morning. 

 

[the_lock_man]

OK, the good news is that your nitrite level is excellent. Ammonia should be at 0ppm, but if you are using the API test kit, the ammonia test is difficult to distinguish between 0ppm and 0.25ppm, so it could well be that you actually have no ammonia either.
 
But as you say, nitrate at 200ppm is not good at all. The reason why it is that high is that, by your own admission, don't do regular water changes. I suspect it's this high nitrate level that is making the fish ill.
 
DO NOT do a large water change - the sudden change in nitrate level will shock them, making them ill again. Instead, change ¼gallon twice a day for 5 days. For the 5 days after that, do a ½gallon change once a day. That will bring the nitrate level down slowly enough that they can cope with it. After that, you need to change about a gallon of water every week, to stop the nitrate building up again.

 

[enordquist]

I will do that! Thank you so much.

 

[the_lock_man]

For future reference, golden danios are also known as albino zebra danios. These fish live in fast-flowing mountain streams in India and the surrounding area. To be able to swim upstream against the current, they are capable of swimming very quickly, so that they can make steady progress. IN an aquarium, where they aren't getting the current, their speed is not restricted. We normally recommend at least a 4' tank, although some people say a 3' is sufficient. Either way, a 2½Gallon isn't really the best environment for them.
 
As it goes, most people would suggest that no fish is suitable for a 2½gallon tank. Can I recommend that you strongly consider upgrading your setup to something bigger.

 

[enordquist]

I've been thinking about upgrading for a while, I'll probably get on it now. Thank you!

 

[the_lock_man]

I've been thinking about upgrading for a while, I'll probably get on it now. Thank you!

 
The bigger the better - larger tanks are easier to control than small ones.