Fear of fish tanks?

Hi there!I've been afraid of certain things since I was a kid and I tried to explain it to someone recently and realized that I don't quite understand exactly what I'm afraid of. I'm not sure if it's water or just vastness, or the unknown (possibly a mixture of the three). I'm going to make a list of the things that freak me out in order of least awful to worst and hopefully someone can give me an insight into what it is?-The banner up at top of this forum's home page (A bunch of dark water, who the hell's idea was that??) -Looking down into fish tanks (not gold fish bowls but like the size of the one's at a dentists office and bigger) -Sticking my hand in a sink full of water to get the drain stopper out. -Video games with water in them. -Enclosed areas of water, even if they water is crystal clear. Like a reef on a tropical island. And even if the water isn't deep. -The deep end of the pool -SeaWorld -Big bodies of water -Dark water -That scene in Ace Ventura where he falls in a dark shark tank (SOOO SCARRRYYY)All these things have water and vastness and the idea of the unknown in common but I don't know how to really define it or explain to another person what it is exactly I'm afraid of in terms they'll understand. Is this thalassophobia?Also, I don't feel like I'm missing out on anything avoiding water and pools, but how do I keep this from getting worse? I used to just be afraid of the ocean but now it seems to be getting worse. (A kitchen sink???)Thanks, Hannah :]