Below I have provided the information requested for posting in this forum regarding my fish and environment.

My situation is this: It seemed to me after my last water change on Sunday, my fish seemed very happy. I was looking at very pretty dorsal fins. Maybe I simply didn't notice it then, but now I notice that often when swimming my two gold fish when swimming will often scrunch or tuck their dorsal fin down.

My question is this: Do HEALTHY goldfish always have their dorsal fins stretched out full in that beautiful way that shows the entire fin stretched high?

INFORMATION

1. - 55 gallon tank, tall not wide.
2. - setup for 7 months
3&4 - two mature common goldfish
5. - PH/8.0, Am/0, nitrite/0, nitrate/0, readings on 5-29-11 after water change
6. - change water monthly
7. - typical size of water change is 50%
8. - water conditioners: Start Right Allantola and Nutrafin waste control and today I added Seachem's Prime .
9. added beneficial bacteria only via the bio-wheels
10. My fish generally look fine standing still. When swimming, particularly when swimming forward the dorsal fin is tucked down.
11. After my last water change, 5-29-11
12. Typically as the month passes between water change, their dorsal fin seems more compressed/stressed.
13. I don't have other fish.
14. no pictures right now, sorry.
15. my filter is a Marineland Emperor 400.
16. I do not provide extra aeration.

Cool. You know the tank looks better too if you are maintaining your tank/water change bi-monthly. It's gotta. And I guess it's time to do the aeration. I'm on a limited budget, but I've had that on my mind for some time.

Thanks.

Understand and thanks. Scrunched and clamped are Goldie's attempt to give you fair warning. Your tank is unkempt. You need to preempt a disaster which leads to mourning.

Goldfish can handle pH from 6.5-8.5, so really, no need to do anything about that unless it isn't a stable reading! If your pH is always 8, leave it like that Don't cause any unnecessary trauma for the goldfish by adding unneeded chemicals to try and "fix" the pH-value.

Yesterday I found out that if you too much food it could rerally change your parameters and myfish had theyr'e fins clamped all yesterday but not today.

If there's too much nitrate in the water (for example, too much food) that is left laying hidden in the gravel or something, it will change the pH values and make the water more acidic. Which is why weekly water changes are so important.

Whenever it's necessary to change the pH in your tap water, for example, if you've got tropical fish who like it more acidic, it's better to have it done before you get it into the tank, so that you keep the same levels in the new water and in the "old".