Well, I may not have thought of that until you said it
but no, I don't think it looks like a coffin. When it's up on the tank and stained to match the stand I think it will look very nice. When it's off the tank maybe a little, but again, I don't think I would have noticed that on my own, and when it's all done I think it will be fine. Even thought you didn't make the stand I think the canopy complements it and both pieces will complement your tank.