No tannins yet, but the fish seem to love it. I wouldn't mind the water getting some color at all. It has too much light decor anyway, it will shine right through.I have some bog wood that has been in my tanks for well over 2 years. I have seen the rate of tannins production slow somewhat but not stop. If tannins bother you, find something else as decor for your tank. You will never be completely rid of tannin production. I do not mind the staining that tannins give my water so I enjoy seeing my fish respond to my wood samples instead.
O.O So... does this mean I can grow a tree in my fish tank? That is AWESOME!Willow is fairly soft wood, although it is classed as a hardwood. You may find that it does not last very long in water. If you got very fresh willow, it will sprout in your tank. The fastest way I know to start a new willow is to cut off a young branch and stick the cut end in moist soil. A few weeks later you will have a new tree started.