Ok...just trying to give a constructive reply...
1) a 240 gallon with oscars, a fire eel, etc. is only NOT going to be a burden to people who love to take care of fish tanks. Especially over a span of time you stated ("years".) Once a fish illness pops up, the eel jumps out, the electricity goes out, a leak starts, a pump stops, a parent gets the flu, or they get a desire to take a vacation, along with many other things, it becomes a burden. Just changing water will be a burden if they have a long work week or pull a muscle.
2) if you want to keep the tank and to reduce the burden, then change the species and choose some small very undemanding community fish. Keep it very under stocked. They will then be more able to go on vacations, suffer through outages, do small water changes, skip water changes and not sweat over getting the flu, pulling a muscle or working late. Even a dead fish caught in the corner and missed will not be a disaster. It will still require maintenance however and nothing will stop that.
Taking it down is however the best way to ensure that it's not a burden.