thanks for the advice. The tank has been running for a year roughly. My fish still don't look any better after the medication today so i think water changes are a possibility.
The LFS said that by using the medication, i would see a big difference within the hour! That is crazy i don't see any difference and i see that they said that just to get me to buy something.
It's abit late tonight to do a water change tonight so i think tomorrow morning i will do a water change.
Would 50% be good? I'm worried as the LFS said if i change the water it will kill my fish as it would shock them. They said it would make the ammonia increase somehow. Advice?
I think your LFS person is a little confused and mixing up two different facts.
Firstly, sudden changes in pH can be a dangerous shock to fish - generally several smaller water changes give the fish a better chance to adjust.
The other thing is that ammonia is more toxic to fish as the pH gets higher. If you were to raise the pH and leave the same concentration of ammonia in there, then it would be more dangerous to your fish. However, if you're doing water changes, then you're removing ammonia each time, so this isn't going to be a problem.
The Amquel+ you're using will convert the ammonia into a form that's safe for the fish. However, having been exposed to such high levels, they will have been damaged and may still not make it. Long term, it's far better to change the water regularly rather than relying on adding stuff to neutralise the toxins. Also the pH crash is not good for your fish, and could be contributing towards their symptoms.
I agree you need to do serious water changes, starting urgently, but as you're using Amquel+ to control the immediate ammonia problem, it might be better to do smaller, frequent ones until you've got the pH back to normal. If you hadn't had the pH crash, then bigger water changes would be best, but I'm concerned that if you do a large water change, the sudden change in pH might shock your fish fatally. Generally, it's recommended not to change pH by more than 0.3 per day, though IME some fish at least can cope with a bit more. Not knowing the exact readings in your tank, I'm guessing a bit at the numbers, but suggest 10-15% twice a day? If you can get an accurate test kit for pH, then you can adjust the water changes to give the best results. Keep using the Amquel+ until you've got the pH and ammonia problems sorted. The cultures you also bought are of doubtful benefit, but won't do any harm.
Then keep doing frequent water changes, and get a liquid test kit if you can to monitor your ammonia and nitrite levels until your tank has cycled fully. Hopefully your fish will pull through, but they've been exposed to some nasty stuff and may not recover. Once things have stabilised, you'll need to keep a routine of regular water changes, to prevent another pH crash and ammonia crisis.
Hope things improve for you soon.
