A few weeks ago I inherited a male betta named Oscar. Poor Oscar lived in a one gallon bowl for eight months. I cycled my 5 gallon tank, treated him for fin rot with aquarium salt and eventually drip acclimated him to the new water conditions in the tank. He seemed VERY happy and was doing great.
Last night I noticed him darting back and forth across the tank then just stopping and sitting in the corner at the bottom of the tank. I have no idea what it is or what to do. I used a magnifying glass to inspect him and I don't see anything. He has been eating very good, perhaps I've been over feeding him. He gets 6-8 bio gold pellets once a day.
After all he's been through I sure don't want to lose him. Tested the water conditions last night and all is good. Ammonia 0, nitrites 0, nitrates 20, ph 7.6, temperature 78.6, filtered tank.
Can anyone please give me an idea of what is wrong??