Thanks for the advice. I've never had this issue before so I don' know if they changed the treatment.
Assuming you are referring to the water treatment by your municipality...check their website, they should indicate how the water is treated. Or call and ask. It is important to know if they use chlorine alone, or chlorine and chloramine. How we as aquarists condition the tap water depends upon what is in it.
To be honest I don' this fish is going to last the night. He' really deteriorated quickly today.
I double checked and tap water ammonia is 0.5 and tank was 0.25 (before water change). So it's bringing it down a little but not enough. There are a few plants in there too.
If ammonia (or nitrite) was the initial issue, these are toxins that normally affect fish internally and from which the fish cannot "recover," meaning that even if it lives through either of these, the internal damage if done is permanent. The fish is weakened from then on, more susceptible to other problems, etc. There is no treatment for this. Secondary issues like fungus can be treated, but treatments also add further stress to fish, and unless it is a certainty that the issue is "x" or whatever, it is usually best not to add substances that may not work, but significant and more frequent water changes are better. However, one has to deal with substances in the source water, obviously. Whitish patches is often connected to ammonia so I would suggest this was the issue.
Second, when using Prime it detoxifies ammonia by changing it to harmless ammonium, but tests will show ammonium as "ammonia," so it may appear to still be present even though ass ammonium. But the change is temporary as I said previously, and after 24-36 hours changes back into ammonia if it is still present.
What are the plants? With only one Betta, live plants, in a 30 liter (roughly 8 gallons) tank, ammonia in the tap water at a level of 0.25 ppm should not be an issue. The plants and bacteria will handle this, as I also explained previously.
So, assuming this fish isn' going to make it. For any future tanks it should definitely be cycled, I treat tap water with Prime, have plants - and that should be ok?
Is there an advantage of having a bucket of tap water treated with prime a day or 2 before water changes? (as it's a very small tank)
If the Betta dies, remove it and do a complete water change. Rinse the filter media in a bucket of dechlorinated water (you can use water siphoned from the aquarium). This will allow the bacteria to remain alive. It should not be necessary to "cycle" the tank, which could only make things worse. I'd like to know what the plants are; floating are best for all this, but faster growing plants do the task (assimilating ammonia/ammonium). Also, what is your pH?
There is no benefit to letting water sit for a day before adding it. Prime and similar conditioners work immediately. And as I mentioned previously, after 24-36 hours the ammonium reverts back to ammonia anyway, so it is better to add the fresh water, with Prime, to the aquarium so the plants and bacteria can begin using it. Nothing will in a bucket of just water.
