I think my favorite fish related customer stories have to be from the time I spent working for Aquatek here in Austin... we really do have colorful people in this city, names have been omitted to protect the guilty.
The weirdest guy was an intoxicated individual who stumbled into the store, blew chunks in the doorway, he'd just eaten a burger and what looked like 6 orders of fries, demanded that I order him a panda, not a panda cory, or panda barb, or panda platy, he wanted a panda bear, he demanded I order the bear or he'd "be callin' the news and makin' them say bad things about me" not the store, me.
Our more regular weird guy was a pushy jerk who blew lots of money on his reef tank that he'd engineered to melt corals and was hellbent on doing things his way, he was always sleazy and rude. We found out what he did for a living.. motherf*cker sold gold coins to people who were convinced the world was going to end and the democratic minority were going to take all the money to a secret moneycave where yuppie morons...err... "concerned Americans" wouldn't be able to get to it, no joke this was his pitch, the screwy part is he'd sell the coins for about 75% more than they are actually worth insisting that gold was the best investment they could make on credit. He took all of those peoples money and pissed it away in corals he couldn't hope to keep alive, I eventually figured out he'd buy literally any frag that flouresced under pure actinics if you gave him a 5% discount.
The creepiest customer got a nickname, "creepy lawyer guy"... I didn't say it was a creative nickname. He had a 30 tall full of platies and danios, couldn't keep cory cats alive to save his life. What made him creepy was that he was in the store every day and talked to everybody in the store about his money problems and make awkward sexual advances on everything that looked like it might have had female genitalia at one point or another. For a while he went through all the girls that worked in the store trying to woo them with a $25 giftcard he'd gotten to Luby's. He is closely followed in creepiness by the giant burly mexican transgender individual who followed me home after I sold him/her some mbuna.
Saddest customer story was a crazy cat lady (the smell and the hair were a giveaway) who came in and had me bag up a bunch of cheap bread and butter fish for her and got violently upset and took a swing at me when I explained to her that we didn't take food stamps.
My favorite customer, a gentleman (I use the term very loosely) who ran a local pool maintenance company, big bichir fanatic, never seen anyone fawn over delhezi like him, always stoned out of his mind, and always offered to smoke up whoever bagged his fish or reminded him where the stuff he bought every week was, and he'd kill an hour doing it. I totally heterosexually love that man, anybody who creates a situation where I get paid to not work and get medicated is awesome. He's followed closely by a young lady who found that my employee discount and an endless supply of feeders could be bought with sexual favors.