Turned out the guy had been in gaol for the past 4 months and upon arrival Katie dicovered a much neglected fish tank. The "caretaker" allowed her to take it as well.
The tank is hexagonal, about 60cm tall and 15cm across which for starters is a really poor design because of the lack of surface area to volume. My son said you couldn't tell there were fish in there unless they bumped into the glass as it was that green and they were told they had been fed about every two weeks.
They half emptied the tank and put it on the back seat to bring home (along with half a ton of nut in a trailer). Katie rushed the transfer of the fish a little taking only a day to acclimate them to her own tank. No quarantine but I guess she could't stand looking at the poor things in that foul water.
Get this though! She found a chop bone in the bottom of the tank! There were more than 30 guppies and mollies in there, many of which were fry and all are still alive. I bet if any of us were that cruel our fish would've died.