To reduce loss, you can make a fish "hospital" like George did to revive his HSB. Buy one 6" Point Four Micropore diffuser, a .1-1.0 SCFM flow meter, a regulator and a small tank of O2. Run it at 40 psi, and have enough bubbles so they barely make it to the surface of the water. That will put more O2 into the water than straight air.

www.hoosierpondpros.com

[Linked Image from lh6.ggpht.com]
http://www.pondboss.com/subscribe.asp?c=4
3/4 to 1 1/4 ac pond LMB, SMB, PS, BG, RES, CC, YP, Bardello BG, (RBT & Blue Tilapia - seasonal).