You know your addicted if
-every single container you see is mentally inspected for possible fish use somehow (would this be big enough to hold a young betta? How would I heat it? I wonder if the plastic is safe for fish (even though it's holding human foodstuff right now)...
-if you get down to your last 2 fish and swear once they die (old guys) that's it, no more bettas, I'm getting a real life, I'm going to make friends who I can go out and have fun with, I'm going to find out what other humans do with their off-work hours--and then find you've just bought 10 more bettas and seem to be thinking about breeding all of them...
-you've been told in March that we're going on vacation in [December] and the first thing you think about isn't where are we going but that the pet sitter will need to be trained how to feed the fish correctly...
-you've been told in March that we're going on vacation in December and you're mentally figuring backward to see when you should do your last breeding until after you come back....