my betta was doing great in his new 15 gallon tank. his ph is 6.5, temp is 78 and he has been fed 3 pellets each of the last two days. he kept spitting out his food but he eventually ate it. when i came home tonight he was lying on the bottom and wouldnt move. i tapped on the glass and he still wouldnt move. finally i woke him up, (i thought he was dead) he is swimming around alot (like normal) but then moving back to the gravel and lying on the bottom. he only lies there for about 30 seconds at a time, then returns to acting normal. was he sleeping?? is he tired?? someone please let me know somthing. THANKS IN ADVANCE!