An agreeable minimum tank size for most Oscars is between 55 to ... Silver arowanas are very long eel-like fish that can grow up to 4 feet long, with 3 feet being more common.

To test this theory, in 2021, they placed young Japanese eels in a tank with dark sleepers, which are larger, carnivorous freshwater fish. They observed that more than half the eels, after being ...