Breather Bags are almost a must (
IMO), as is fast shipping. Depending upon your location and your shipping to location, you may need to go with an insulated container containing a cooling pack...it doesn't matter how well you pack your fish if they are sitting for 4 hours in a FedEx truck in 110 degree Arizona heat. There are also these little tablet-type things (dang forget what they are called right now) that you can put in the bag that will absorb any ammonia excreted by the fish. Not sure if that is a necessity but it certainly couldn't hurt.
In the end, you really need to consider whether all of this is worth it. You need to invest money in the Breather Bags, the vacuum sealer, the right size boxes, appropriately cut styrofoam to pack all around, possibly these ammonia tabs, and possibly cooling packs. All of those are expenses you are going to be "eating," unless you pass them along to your buyers in which case shipping costs, which already are going to be high, will end up being even higher.
On top of that, you need to be prepared for the reality that, if the fish are DoA, you need to refund all the money paid by the buyer.
You also should ask yourself, given that a potential buyer is probably looking at $25 or more just in shipping fees (and more if you decide to pass along the cost of your shipping materials), plus whatever you are going to ask as the selling price for the auction itself...are your fish truly that valuable that a buyer would consider it worth it? I don't know the market price on ciclids well, but if indeed someone could go to a
LFS and pay $30 for one of these, then it makes no sense for them to buy such a fish from you, even for $5, considering the cost of shipping is going to mean in the end they are spending about the same money for a much riskier proposition. Even fish that survive tend to be quite stressed out as a result of shipping, which makes them more susceptible to disease during those first weeks, right at the time they are suffering the additional stress of adjusting to a new tank. If you have no history on Aquabid, you can expect many potential buyers to not even look at your auctions as well. (Just like on ebay; buyers are always a bit wary of someone with zero feedback who is suddely selling stuff. The more expensive the "stuff," the more of an issue this is.)
Also, I'm not exactly sure why this is, but it seems to me that adult fish tend to not ship as well as juvies. I'm just imagining in my head the kind of banging around a 6" cichild is going to suffer in a box getting shipped...not a pretty sight.
Anyways, just some things to consider. If I was in your shoes, I might first try contacting the Indianapolis club and seeing if they could advertise to their members that you have a tankful of cichlids that you'd like to sell to one buyer...you may get a cichlid lover who is willing to take a Saturday and drive down to you and take the whole lot off your hands at once.