The five smaller blues had gone to a new owner in Ft. Lauderdale about half a year ago.
Lost the big blue. 22". 8" tall. Probably 5-6 yo, but could easiy be 8-9 yo. Collected from the koi pond at 10", at which size it could be 2 years or 5 yo as they don't grow big fast in fierce competition.
Either age (I read they live only 9 years) or the regular harassments by the 2 foot Nile tilapia tank mate (for which purpose I moved out the Nile bully only a few months ago to the neighboring 4500 gal) or the current Microbe-Lift broad spectrum disease treatment (malachite green + formaldehyde), which I have been administering after cleaning the 15,000 gal sump, which caused a mild outbreak of some external pathogen. No other fish has been affected that bad though by the treatment, everyone still feeds, so I am not sure why a bulletproof tilapia would quit.