Yeah I have a filter with an air pump to circulate the water but I wasn't satisfied with it, didn't think it was giving him enough oxygen?
When I first set up the tank I have it on full but then realised it generated a strong current then read fish don't like it as it acts like a fast trendmill and makes fish feel tired so I turned it down.
He does gulp sometimes at the top of the tank, but sometimes Im not sure it's because he doesn't have enough oxygen or he is playing with bubbles? Because he loves bubbles!
As an update I have managed to use a fake plant to hold the tube in the water and I have got a bubble wall coming in the post. I've always wanted one and it will put me at ease that he has enough oxygen in the water!
Maybe for Lucky it was like a little security blanket?