I returned home from work and went to feed out the fish like I normally do. I was horrified to find my leichardti pale and floating at the surface. I did water changes to a dozen tanks yesterday, including the aro's 150gal. Parameters are null with DO reduced slightly (probably from the aro's decomposition). There are no other fish in his tank. He was a grail fish that I intended to keep separate of all other fish. I got him. as a 4-5" juvie, last summer and was getting ready to relocate him to a 250 gal. All of the other tanks that received a water change yesterday are fine. The fish are well colored and eating/acting normally. His diet has been devoid of live fish for the last 6-7 months. He's fed gut-loaded crickets (loaded on hi-pro fish flakes w/spirulina) and arowana sticks.
Sorry to hear that.
