Pet Beta Fish

He tries to eat, but still lacking, while for the food pellets, or it is just at the bottom of the tank.

If he is hungry he eats

Warm water. Bettas, as 80 degrees Fahrenheit or more. All cold and their digestive system is not working well, and they are too uncomfortable to eat.
If you have a heater running, add half a teaspoon of aquarium salt for each gallon of water. It helps stabilize the body chemistry of the fish.
Change water. If you have no mechanical filtration, you need to change the water every two days. If you have a filter, change 10% of water every two weeks.
Betta fish need at least one gallon of water. They can survive in smaller, but would you live in your closet? It's the same thing for them, and keep in mind that they shit in there too.
Is a good site. Many info
www.bettysplendens.com

Ok, listen Bonsylar, but it is easy to take on salt. Some bettas do not tolerate salt at all. Unfortunately, there is no way to know if your betta is sensitive or not until you put it in water with salt.

Begin slowly - use only one teaspoon per five gallons. Finally, you could make two teaspoons per five gallons, but keep the light yet. If your betta starts to show signs of distress after adding salt to an immediate water change of 75% (using dechlorinated water at the same temperature) to dilute the salt. Then, make changes daily 10% for a couple of days.

Clean hot water can work if it is not sick? Good luck!

My betta did the same thing. At times, without apparent reason, he stops eating. At the moment I am getting concerned, it begins to eat. I do not know why this happens, but there seems to be something of a model with him. Most fish can go several days without eating - there is no need to worry unduly.