After about a day (if there's any left), it will start to break down and pollute your tank. Also be advised that cucumbers are messy to feed because you will probably have a lot of seeds left over. Zucchini is less messy.
Thanks. The seeds were the first thing my BN went for and the I didn't have to worry about having to keep it from floating. When I woke, there was just the elastic around the rock and the belly of my BN and my loach were very full.