My big Clarkii has been swimming erratically today. Seemed to happen overnight because I didn't see anything wrong the previous day, and I check each fish daily. Other fish are acting as usual in the tank. It seems like her pectoral fin is stuck forwards, but occasionally she will swim normally as well. Like right now, I'm watching her swim normally, but she does seem a little slower than usual. She's eating like normal. The video below shows the 'stuck' fin, which occasionally goes back to normal. Perhaps there's something bugging her or is a thing they just do? Or do I need to take immediate action?