There is some evidence that fish may recognize their owners, but the results are still inconclusive. A study by Duke University in 2006 showed that when household pets were introduced to new environments, the pets whose owners had been Away for an Extended period of Time (6 weeks) spent more time in the open area flown into than did Pets whose Owners were Present at All Times during Training. However, when a stranger was introduced as a comparator pet, there was no difference in time spent in the open area between Pets with and without their Owner present at all times during training. The study did not measure whether fish recognized their owners.
A 2006 study by Vlatko Andjelkovic at the University of Vienna showed that goldfish (Carassius auratus) trained to distinguish different colours of food exhibited greater preference for food presented near their owner rather than food presented 3 m away from them. The fishes also orientated themselves towards their owner more often when they were given the choice