No no... You don't have to just follow my advice. Every situation is different, and sometimes, you need to decide what the best treatment will be, given the history of the fish, its current condition, etc. Also, everyone's approach to caring for our Bettas is going to be a little different. That means that all of us may vary a little in the treatments that we follow. Some people are quicker to prescribe medications, others prefer a more holistic/natural approach. In the end, it's up to the fish's owner to determine the best course of action to take.
As for using 3 tsp Epsom salt/gal, I personally just recommend it for 'severe' illnesses/issues. For example, if a fish has dropsy, etc. Then, since the next step beyond dropsy is often death, well, if it was my fish, I'd keep using that dosage and not really worry about a specific length of time. But, again, this is my personal philosophy, not any 'definite rule.'
On the other hand, I have a fish who tends to become bloated easily. I just use a low dosage of Epsom salt when this happens. Since this is my fish, I know what works, which is usually about 0.25 to 0.5 teaspoons Epsom salt per gallon. As soon as he poops, or becomes less bloated, I do a water change to remove at least some of the Epsom salt.
So I would say that, again, there's no 'hard rule.' You have to look at the pictures and read the history. But usually for nonsevere bloat/constipation, I'll recommend:
- 1 to 2 days of fasting to see if it helps.
- A dosage of about 0.5 teaspoons Epsom salt/gal for 1-2 days. (And if that doesn't work, then go up to about 1 teaspoon Epsom salt/gal.)
In the case of internal parasites, it also depends on the fish's history/condition. If the fish is bloated, but we're not yet sure what's causing it, then I'll recommend Epsom salt.... But if we're sure that the problem is internal parasites, I'll recommend a medication that contains both metronidazole and praziquantel. (For example, API General Cure.) This is because these two medications treat the majority of aquatic freshwater parasites. Then, if the fish is also bloated, I may recommend using a low dose of Epsom salt to relieve this.
There was a study done recently that indicated that Epsom salt can expel parasites. It was a pretty high dosage of Epsom salt needed for this, though. So for people who prefer not to use medications, using Epsom salt for parasites is another option. So, in this case, the treatment you suggest is not only based on the fish's history and condition, but also the ability and/or willingness of the owner to get medications. Some people prefer a holistic approach, some people can't afford medications or can't get them at local stores, etc, etc etc.