Your aqaurium may not have sufficient dissolved oxygen in the water for your betta to thrive. Try and aim your filter towards the surface to adgitate it a bit more. How long has your tank been set up for? Has it been cycled??
Matty
We've done that and now he has disappeared from the top! :can you post your water stats:Ammonia:Nitrite:Nitrate:Move your filter near the top so you have more surface aggitation as matty p saidorange shark
He is not alone in the tank, all the other fish are OK in the tank.We have been set up since March of this year.Your aqaurium may not have sufficient dissolved oxygen in the water for your betta to thrive. Try and aim your filter towards the surface to adgitate it a bit more. How long has your tank been set up for? Has it been cycled??Matty
... Bettas breathe from the surface, and turning the filter up would only create more stress from the current.