My fish are my babies. I'm only 19, and don't plan on having kids for a LONG time, if ever, but I consider my fish (and my cats) kids.
If I can tell my fish from the other ones, then they have a name. My blood parrot is Anya (Anastasia), and I never say "the blood parrot" when talking about her. My gold gouramis are Artemis and Aphrodite, and my female bristlenose pleco is Roxanne , my male bristlenose pleco is Haiku (Spirited Away :0), my new angelfish is now Kairi (Kingdom Hearts), my male betta is Miles (Surface), and my snail Poseiden. I'll probably eventually name some of my favorite platies and female bettas. I usually don't cry if my fish die unless it's a baby (and not a fry from a platy, but like a baby cory or synodontis) or I am really attached to it. When my female pleco, Emily, died a few months ago, I was devastated. I was crying, and really sullen and sad by it. And that normally doesn't happen for me. Generally speaking if it's a catfish or pleco or betta (or a larger fish I only have 1 or 2 of) then I am sad about their deaths. (I've also noticed I care more for my females then males, but that prob stems off the fact I love little human girls over boys, but oddly enough have more sympathy for males in movies/books/life then females)
I give my fish feelings, and frequently talk to them and feel bad (say if I was netting them or scared them on accident, or "scold" them

) for them. Or say they are happier in one tank then the other, and refuse to downgrade tank sizes for my fish. (When I was selling platies, the smallest tank I would sell them to was a 25 gallon, and they had to have live plants or at least silk plants), the exception of this rule is my male betta. I moved him to the 55 gallon because I had to put my shark in a tank where I knew he couldn't kill anyone, and moved him back to the 29 gallon because he seems much happier there (less current, slightly warmer, better overall for him), but I would never move him to a 5,10, or 15 gallon.
I will spend so much time just watching my tanks, in my living room I have my one 55 gallon (Amazon themed), on one wall next to the tv, and then on the other wall next to it, I have my other 55 gallon (more river bed themed) and further along that wall, I can see the side of Miles 29 gallon bachelor pad. So rather then watching tv, I watch my fish. My sister will call because she is happy about some new clothes, I respond how I am THRILLED by my new plants and how amazing my tank looks! The first thing I ask my boyfriend after having people over is "did they say anything about my tanks?" (normally yes- why do you have so many fish tanks? *in disgust* WTF?!) I spend so much time talking about them, and thinking about them. Fish, mainly my fish, make up who I am.
Nothing will put a smile on my face more then seeing a tank of happy, healthy fish. Nothing makes me feel sadder then seeing a poor betta in a bowl/cup, or fish overcroweded. I will have frequent night mares in which there are bettas kept in horrible conditions, or where I forget I have fish and then find my tank to have only 2" of water, everyone starving to death. But mainly it's just horrible stuff with bettas.