We don't say jerk here is the UK but most of our words that are like jerk are actually really inappropriate and count as profanity so will use US lingo :)
Kyon is such a moody grump! He flares almost all the time at everything and anything and gets upset pretty easily. I fear if he was human he'd be one of those people you'd really dislike for their attitude problem. He's like a teenager. A few examples, he was flaring quite violently the other day, couldn't put my finger on why, 10 minutes later, he's take a chunk out of his tail and a quite a bit of the floating plant has been shredded. Must have been in his way. He bit my finger again yesterday while I was trying to pick up a pellet off the surface that had gotten mixed in the duck weed, he then proceeded to flare at me rather ferociously (gill covers out and everything!) and sulk in his pot. Other times he will get an angry stress line if the light is on for too long or not long enough. The line comes out we know it's either lights out or lights on! He sorta stalks between the plants like something from Jaws!
I think we'll be giving the shrimpy tank mates a miss. This guy is obviously solitary. Anyone else's fish just an ass?