Would you raise a puppy in a closet? Would you leave a horse in its stall for the entirety of its existence? For which species is it "acceptable" to provide less than an adequate environment, and what criteria do you use to make that determination?
This is the problem right here. People don't understand that fish ARE NOT dogs, fish ARE NOT horses, and fish are most certainly NOT human beings. Don't compare two un-related animals to the same scenario.