I hate this. I sort of have fish tanks everywhere, they spread when I ran out of power points, so you kind of do notice them. When we have visitors, they look at my tanks, and then usually say: "Is there only one fish in there? Why is it so big for one fish?" or something along that vein.
The thing is, one of my fish has about 8 gallons to itself while the others have from 3.5 to 7 gallons each, so it's not like their tanks are huge. I then have to patiently explain that fish like having more room to swim around and explore, plus maintenance is easier on larger tanks. If I wanted low maintenance, I would go find that pet rock we liberated into our front yard when I was about five.
It seems whenever I mention I own fish to anyone they tell me: "I had fish once and they all died". It has gotten to the point now where I just finish their sentence for them, and then go on to explain cycling, water changes, proper care etc. Everyone at work now refers to me as the Crazy Fish Lady.
Another 'good' one is when people suggest I should put my fish together and fight them. Because supposedly it's fun to watch my pets maim and kill each other. Sometimes I think our gene pool needs some bleach.