I generally don't care for the lily vase set-up but in this case I
would have to agree with Elaine. If you've had him in there for 3 years
he is probably already between 3.5 and 4 years old. He's getting up
there in age and any changes in pH or other water parameters may cause
complications not to mention social stressors. I, personally, would let
him be if it were my choice.