i've seen something similar in swimming pools in the back of a house on lots i've created and in windenburg's public swimming pool.. sometimes the water can be refreshing to swim in, othertimes it is too cold and the sim turns blue, sometimes they get this complaint about swimming in chlorinated pools, but that isn't the same as saying they have a phobia.
At least no one is watching Jaws or Piranha films and having those thoughts about being eaten alive by a fish in the deep dark ocean just suddenly. Those with thalassophobia, the fear they get from big dark blue oceans with dangers lurking in it is magnified many times over than one gets from nightmares and an aversion to going into deep water thinking they are going to be killed by some hungry fish from a film. ofcourse aquaphobia is different from thalassophobia.