Hi Interfecus,
It doesn't appear to have an "arrow" shaped head. I've done some looking around and the closest thing I've found to what it looks like is thread worm.
I havn't seen anymore since doing a major water change, but i'll keep a closer eye on it over the next week.
Should I go as far as dosing the tank with anything or should I just go with doing water changes every couple of days?
Thanks.