Hi - we had a few troubles a couple of weeks ago with changing water & filter media in the tank, about the same time oscar developed a white circle mark on his head, which now appears to have healed, so I think it was a knock mark. The water is good now, but Oscar has been behaving very oddly for over a week.
He sits onthe bottom, apparently sulking, or staring at his reflection - doing the flaring gills thing at his reflection and he has taken to biting the filter intake, and some of the decorations in the tank. He's also doing this crazy swimming in circles - he looks like he's chasing his tail - its very odd and doesn't seem to be calming down, he dug a big hole in the substrate & I read about the reflection issue - so I filled it back in, he's been moving it out again, but mostly doing this odd behaviour of sitting, swimming in circles & biting things.
any ideas?
