-Never top off your aquarium at "Omigod o'clock" in the AM in the dark. Trust me on this.
-Don't think that this is the one time you'll be able to skip rinsing that bag of gravel because it "looks pretty clean."
-Don't start re-arranging "just a few" rocks in your tank before you head out the door for work, or you'll be calling in sick within the hour. You will.
-Never setup a new reactor, lighting system, or anything involving multiple plumbing connections prior to departing on a trip of pretty much any duration. Just don't do this.
Don't assume that "it's all good" because you have an electronic controller monitoring everything. Nope.
-Don't put that cube of brine shrimp or frozen bloodworms on the shelf in your closet to thaw a bit while you're putting on your tie before rushing off to work. You'll no all about why at 5:30PM that night. Enough said.
-Never tell yourself you're just going to pick up just ONE pair of new fish at the club auction. Won't happen. Forget that notion altogether.
-Don't reach into the tank to make that "quick adjustment" on something without having a dry towel handy. Do this once with the skeptical spouse/roommate/significant other around and you'll know exactly what I'm talking about.
-Don't think that this will be "the last fish" you add into your tank...
-Never log onto a fish auction website just before a major bill is due. Yup.
-Don't believe that you'll be the one guy who can keep multiple Centropyge angelfish in a 55 gallon tank without bloodshed. You aren't.
-Never assume that the siphon hose is in the bucket before you start it. Please believe me on this.
-Don't assume that you have "one more outlet" left on that power strip. You don't.
-Never try to "shake a small amount" of fish food right out of the can into your tank. Nope.
-Don't believe the words "easy to set up" in reference to an aquarium component. Especially when the component is of international origin.
-Don't forget to stop at the AM before your next fish club meeting. Seriously.
-Don't fool yourself into believing that you can net that fish that's been terrorizing your tank without pulling out all of the rocks and driftwood.
-Never believe that your new fish won't need to be quarantined "because the LFS does it..."
-Don't think that you'll be able to house and raise all the fry from that pair of cichlids.
-Don't believe that you'll just be satisfied with one aquarium! You suffer from "Multiple Tank Syndrome" and may not even know it. Yet.
And never forget to...