Fluther is a question and answer site, not a marketplace. According to question guidelines, questions must be “genuine, well written, and promote good discourse.” A question posted as an attempt to sell your fish tank would not fit those criteria. Odds are good it would be pulled fairly quickly.
I would ask a question to enquire where is the best place to sell it, that should be ok, and if any users are interested in it enough they would no doubt message you with an offer or something.
I can’t see you getting away with much more than that.
It would be considered self-promotional and/or spam, so no, you cannot sell things here. @poisonedantidote does offer a good roundabout way to do so, but if it has blatantly been asked only so you can find people who are interested in buying your fish tank, it will probably still be pulled. I would just try to stay away from this type of thing on this site in general. Really, there are many much better places to sell on, anyway.
If you ask for suggestions about where to best sell a fish tank, how to market it and what you should (and should not) fix before you sell it, I’m sure we could give you a great collection of advice.
Don’t try to sell products directly on Fluther. The requests will surely be modded, and if you persist then you’d find the account closed. (And I’m not a mod.)
Nope. You can’t. Not the place for it. @augustlan is the community manager here. Her answer on this type of thing is definitive so that’s pretty much it. You can’t do it here.
I am just selling locally… The price is pretty reasonable considering the items included. I thought Fluther might have some peeps in Austin that were interested.