I raise a lot of fish, and when I drain the filters, I get a sludgewater slurry of fish poop, living and decaying algae, and multiple kinds of beneficial bacteria.  Here's what it looks like compared to a cup of clean water:

Idk the details but have you checked in the larger flat rate boxes? For those weight doesn't matter. If it fits, it ships! Lol just a thought.

Or maybe that is it? Sorry just thought about it and those larger flat rates are probably that much. Should think before speaking/typing sometimes lol

Don't be sorry, I appreciate all the help I can get figuring out how to ship as cheaply as possible!

maybe you can dry it.
really no point to ship H2O.

I raise large gold fish for aquaponics and you are correct, this is high density fish nutrient in a bottle.  We save every drop of this annual 'clean out' filter water we can get our hands on. Fantastic on house plants and I'm sure it would be a real tonic for starts. I had an orange tree that just drooped- it had all it's leaves but it literally drooped. I fed it a generous portion a couple of weeks back, and there was a greatly noticeable difference in just a couple days.  The other plus is, I don't think you can over-fertilize with this. I hope this works out for you.  The price seems right as well!

I have had a 140 gallon tank with a big canister filter and i did the same,thing. It is now full of figs. I saved all the gravel in big ice chest. Still has some of the tank water in it. And it doesn't stink. Amazing stuff.

Don't leave it bottled too long or it will go septic (anaerobic).  All the beneficial microbes will die and be replaced with undesirable ones.  
 

Yes, youre right, Charlie...stagnancy will kill the good microbes. I keep an air pump in mine and it just bubbles until i use it up. It takes me about one month then i start over again..,whenever I need to. I bout a small pump at Walmart with two hoses. It was cheap like about $10. This just helps the good microbes continue to multiply.

I think I may just keep using all of the fish poop on my own plants and not sell it.  It's a great resource for me, but it's hard to share a meaningful amount because shipping is so prohibitive.  Plus, as Charlie mentioned, the beneficial microbial ecosystem would have a short shelf life.  Add to all that the fact that it would be a hassle to bottle and ship, and I've already found myself hoping that nobody will order any.

Dehydrating it via some low/no heat would be the way to go.  Making an income on an otherwise waste product is just good sense, look at grapeseed oil, other organic fertilizers, etc.

I looked into dehydrating goat milk whey after making cheese, healthier than whey proteins sold to fitness/body builders, but turned out to be too expensive for my small setup.  I feed it to my dogs and pour it on my compost piles.  

If your setup is large, dehydrating might be worth it for you.  Have you looked at organics similar at hydroshops? This is still (and will be for some time) a huge growing market. 

If you didn't want to dehydrate, In our area we have people who sell only activated aerated compost teas, maybe think local?  This usually last a few days or more once bottled.  I wish you success.