Last is no compost at all, weelll, maybe. This is my rain barrel that you could see in one of the above photos. Perhaps this could be called fish compost.
I originally tried mosquito dunks, because the mosquitoes became really bad in the barrel. They didn't work at all (for me anyway). Then I tried putting screen over the top, but it was a complete pain-in-the-rear to remove every time I wanted to dip out water. So I tried installing goldfish, and what a blessing those goldfish have been. Poor things though, started out with 10 tiny ones at 20-cents each. Right away, a few died. The first winter I bought a small plastic aquarium for those 7. Way too many for a small aquarium even if it does have a filter and pump!!! So all of those perished but 4, and then 2 more perished upon returning them to the barrel. The amazing part is, that last winter I just didn't care to make the effort to try to catch those 2 fish . . . they were *very* difficult the first round. So they were left in the barrel. They somehow survived the winter in that barrel. My mom and I were both amazed as that thing froze almost solid from what I could see. Who knows what will happen this winter.
I'm sure my potted plants enjoy the fish emulsion they get when I water from the barrel. No mosquito larvae now!
The interesting thing about this photo is I was paying so close attention to try to snap the shot when the fish were together (they were swimming around), that I didn't even realize I had a reflection of the maple tree and the house siding in the water.