I want to feed my fish zucchini, so when I went to the store recently, I got a couple zucchinis. However, I don't have easy access to a grocery store. Could I slice up the zucchinI and freeze them? Would they still be good for the fish? Also, I'm not sure if they're organic, I forgot to check. Does it need to be organic, or would it be fine if I just washed it well first?