On their way to trouble FOR 5 YEARS?
This tank is constantly kept up with carbon changes, all water changing is done while vacuuming gravel, there is UV sterilization, there is nitrate removal media, there is never any overfeeding, the water is completely covered to prevent evaporation (and the chemical build-up it causes), there is twice as much bio-media as needed and chemistry is constantly monitored.
You can easily judge a tank's health by the health of the inhabitants. My fish have NEVER experienced an illness of any kind, are very brightly colored and are in a constant state of energy and alertness. I understand it takes a lot of responsibility to care for my friends and I'm more than happy to help 'em out. They all enjoy being petted (although not recommended for fish health concerns) and being hand-fed.
Also, remember that they haven't been this big for the last 5 years. I know that 3 2' active fish would like more than 125g, which is why when I move in 2 months, I'll be taking advantage of the opportunity to upgrade to a 200g.
The Alligator gars grow, in the wild, up to 9' long (the florida gars, only 3'). Eventually I'd like to have a 10'x12' or so pond in the back yard for them and the Arowana until they get TOO big. At that point I'll take a road trip down to the southern states and release them into their native waters. The Arowana I'll be able to keep as they only get to about 3'-4'. Probably pretty pricy to transport 2 5' fish

Better start savin' now!