hi this is the first forum i have been on so bear with me if it takes awhile for me to post or they end up on another stream. anyways i have a about 1000 or more indoor pond. with a three inch bottom drain that goes to a self built acylic filter. some of the acrylic is clear and some is blue. the filter is 3 feet long 12 in high and 12 in wide. and i have a 2250 gph and 1250 pumps running my pond. ok now that is out there. one of my large fish died. i have never had any problems with my koi before but he was acting like he wasnt getting enough oxygen and would try to stay at the top of the water wo he could get as much oxygen as possible. i tried medicating the problem with some medications for aquarium fish but he stayed that way and died. i thought it was an isolated case but now one of my favorite fish is acting the same way. does anyonehave any ideas