The usual answer... I'm not surprise! You called me "boy," claimed that I'm "king of craming big fish into small tank,' but when was asked to show which big fish was crammed into small tank, you changed the subject. I haven't claim I'm better fish keeper, or put other down. I'm not that insecure person, Al D-az! Now, let's try again! Care to show which big fish was crammed into small tank?
You can answer your own question by posting a full tank shot of your 600G. It's only going to get worse as the Albino Pacu (3 of 'em?), Wels Catfish and 12+ GATFs continue to grow...that is if they live long enough. The crazy part is that's just the tip of the iceberg...you have many more fish that will outgrow all of your tanks.
The gist of what I am saying is that if you plan a tank with the full or even the expected average size of a fish in mind and keep the number of fish within reason, you will have much greater success. You won't have to do 80% water changes 3 times a week just to keep your Nitrate levels below lethal or at the very least harmful levels. I know you will be offended by my advice...after all, you are a "pro." But I guarantee you would have much fewer losses if you thin out your coin collection.
If you continue down the same path I guarantee the pile of dead fish will continue to grow. I don't care if I don't convince you, but I know there are some noobies that are taking the time to read this thread that are starting to think for themselves...maybe there is a better way to keep fish...maybe instead of spending all their money on obtaining exotic species, you should invest as much if not more into an appropriate environment for them to live?
A few people have mentioned PETA and how they are concerned that the organization is going to ban fishkeeping alltogether. I guess it makes sense that some of the people most afraid of PETA are the same people giving the organization ammunition to put an end to our hobby. When you set out with the frame of mind that you are going to hoard as many huge fish as possible regardless of any tank size limitations, it reflects poorly on all of us. When you base your stocking decisions on your own impulsive desires without thinking and planning for the fishes future needs, you are being selfish and unethical. It's the MFKers with massively overstocked tanks, pix of fish that have torn each other to shreds due to the owners ignorance/incompetence that make us all look bad.
If more people had setups that looked like Jose's, you think PETA would be able to garner any support to put an end to our hobby? Again, I'm not against keeping monster fish and I'm not suggesting everyone should only keep discus or little tetras. All I am suggesting is to be practical and use good judgment. That should not be controversial, but for whatever reason it is.