Thanks Pink Fish, what I will do is something up for him tonight, he's sulking in the container I have for him now (as soon as he sees me he lays really still, but when I watch him from a distance he's darting around in there, plus I think he can see the other fish so not happy, he is still really active but the "wound" looks really awful and sore, having said that...this morning I notice its going kinda white around the outside of it so that will probably mean its starting to heal (god I hope so anyway) poor wee guy. I'm going to invest in a heater guard anyway, because if this is a heater burn I don't want any of my other fish to have to go through this.....