I like the crayfish idea though i might have to set up something other than the clams to contain them as they like to go walk about.
I have and know of a few spots withing 40 minutes of my house that hold tarpon from time to time, i've even caught them in tinny creek which would be ideal. Pools got about 25 000l in it now and i can't put much more in until i have some more rain that puts some water back into the tanks so tomorrow i'll put some lillypads in and put in about 3.5kgs of mineral salt and then some time this week i'll go convert some bream and poddy mullet, it all seems to be moving along nicley, can't wait to have a bunch a decent fish swimming around just past my back veranda.