Ed.: Today I have come to drive you crazy with another trapping/muktzah “permutation”: How is it that fish can be considered already trapped before Yom Tov starts, but there is still a muktzah issue? [This will probably never happen to you, but the thought-process is fascinating… (to me, how about you?!)]
Here’s the scenario: A stream, carrying live kosher fish, flows through a very narrow “canal” – no more than 6 tefachim (about 18 inches) wide. Before Yom Tov you place one dam up-stream and one down-stream, so that a number of fish are stuck between them, and all you have to do is reach in and grab them. This is not a violation of tzod/trapping on Yom Tov. Based on our previous learning, we would probably assume that the fish are therefore not muktzah, right? Well… they’re not muktzah on account of their being in-accessible due to trapping, but they may be muktzah due to the number of fish. (Huh?!) Let’s say there are twenty fish in that small area, and you are sure that only need six of them. Theoretically, any individual fish you pick up, up to six, are ‘muchan’ (lit. prepared – not-muktzah.) However, they are not all ‘muchan’ – because you knew that you did not don’t need all of them! So, you ask, why should I care – I don’t need all of them?! Ah… but this means that you can’t “shop around” – i.e. picking one up out of the water, looking at it and deciding to throw it back in and pick a fatter one instead! Get it? Now, if your thinking is that you’re not sure how many you will need, and possibly even all of them, then they are all ‘muchan’ and you may shop around, even if you end up not taking them all!!!
Isn’t this neat? What’s interesting is that these principles are all taken from the halachos of Shabbos, but the applications are purely unique to Yom Tov, because you would never gather raw fish on Shabbos, since you would not be able to cook them! On Yom Tov, the halachic possibilities really open wide!