I finally transferred my betta to a 5.5-gallon tank with heater and filter. He seems okay. Swims around a lot but stays close to the top. Doesn't swim in the middle or bottom of the tank. Is this normal? He eagerly comes to the front of the tank hoping to get fed. Also, he swims by the filter a lot and seems to enjoy putting his face near the water coming out. Sometimes it pushes him down but he keeps going back to it and chases the bubbles it creates. The filter is set to the lowest level to reduce turbulence. Is it possible he's enjoying that or is he really suffering in this tank?