Just adopted my (nameless) mustard gas betta yesterday. I went to feed it this morning, and he only ate one piece of food, meanwhile I fed it 3 pellets. I understand I am supposed to feed it 2-4 pellets, twice daily. The other two pellets he kept spitting out. Are the pellets maybe a bit too big? after two minutes passed, I cleaned out the uneaten pellets. About ten minutes later, my poor boy throws up the only pellet he ate. Of course I cleaned it out afterwards. At First, my fish seemed hungry still, but I didn’t feed it because I was trying to figure out what could be wrong with him or the pellet. Now, an hour or so has passed, and he seems back to normal. if it is just an issue with the food, I can easily just break the food or buy new food, but I’m worried it might be something wrong with him. I can put tank information below. The fish was not injured when I got him. His behaviour has not changed. He is not eating. It is a 3.5 gal tank with filter. I do not have a heater because where I live it is always very warm anyways. His current tank temperature is 79 degrees, or 28-29 degrees Celsius. All his decorations and tank have been cleaned in just water. All the decor is fish safe. The filter is betta fish safe too. He himself looks perfectly fine. No spots or tears in the fins, his eyes are fine, and his colour is bright and beautiful. What could be wrong? Could it just be the food? Here is a recent Picture of my little betta. Thanks in advance.