I am not so sure about that. Maybe you can relate a little to the needs of mammals but fish and reptiles are wired totally differently. For example as mammals we like touch from our parents and others because our parents took care of us. Reptiles or fish who never even saw their parents don’t have that concept. It’s foreign to them.
On the other hand ;), it stands to reason that confinement or restriction is something many species including fish and reptiles will grow impatient with. After all, there is no evolutionary advantage to letting yourself be locked in, for nearly any animal.
A fish species may have a strategy to stay hidden in a plant because swimming in the open is dangerous and ambush whatever swims by. In that case giving them space to roam won’t make them happy but they need things to swim by. Again, look at the natural behavior.