During the past few days I have noticed that my betta has started to flick against plant leaves and objects in his tank. Other than this his behaviour is normal, he is very active and still eating like a pig. Does anyone know what this might be a sign of? He has been in the tank since October last year and has pygmy corys and kuhli loaches as tankmates. The water stats are 0 for ammonia and nitrite, and 20 for nitrate, ph 7.6. I also think he is starting to do it more often than he was.