He seems to frequent the top right front corner of his 10 gallon tank. There is no filter , because the one i had is too strong for bettas. He eats normally, flares, and has made some sort of mini bubble nest in the top left front corner of his tank. However, since yesterday, he seems to be breathing hard. I fear he may have swallowed a pebble and it is lodged in his throat. Also, he seems to swim only in the front of the tank. His behavior changes a lot at night, he swims near the bottom and stands still for several seconds. I got this fish from this place called Pisces Reef in las vegas. Is there anything wrong with him?