Oscar

I think of the freshwater South American Cichlid 'Oscar Fish' which is well suited for a larger aquarium but a bit temperamental and fairly intelligent for a fish. They are very territorial ruffians and will rearrange the plants in the tank often killing live plants or simply knocking over artificial ones. I found that simply decorating the aquarium with pretty pieces of driftwood and a river pebble base was best if you want to go with an Oscar tank. They love live feeder fish but will consume various berries, nuts and veggies. Special pellets are also available for their keeping. They can grow to be a foot and a half long in very large tanks and are a common food fish in certain South American countries.

I think of epic sets like this one:

https://youtu.be/gK3gvW5TpvU

I think of Oskar from Let the Right One In (2008)