Everyone has Water Signs in their natal chart.
And how strong Water is in their chart has NOTHING to do with their "zodiac Sign" (properly called their Sun sign).
They may have their Sun in a Water sign, but NONE of the OTHER 9 planets will be in Water Signs.
They may have 4 or 5 of their planets in Fire Signs, in which case they will be far MORE like Fire Signs than like their Sun sign.
You need to learn how astrology really works before you try to draw assumptions. If you use only the Sun sign (just 2% of someone's unique natal chart), you will be drawing erroneous conclusions that make you unable to understand the people around you.
“Many people think that astrology is the Sun-sign columns found in every newspaper and online news media sites. Nothing could be further from the truth. That’s not astrology, that’s entertainment, which is what’s often stated in the fine print beneath astrology columns. Unfortunately, Sun-sign columns are one of the most persistently misleading representations of astrology. “
(Dorothy Oja: “What Astrology is and isn’t”)