Is there an issue of Tzeida (trapping) with regard to fish? 

As mentioned in the previous sheet, trapping an animal on Shabbos is prohibited. It was also mentioned that hunted species are biblically prohibited to trap and non-hunted species are rabbinically prohibited.

Fish fall into the first category and are biblically prohibited to trap, this is because they are hunted for food or as ‘pets’ for household fish tanks. 

Does this apply to fish in a fish tank as well? 

Notwithstanding the muktze issue, it depends on the size of the tank. A fish in the sea or a lake is subject to the fundamental prohibition because in its present state it is totally free. A fish in a small fish tank would not be subject at all to the prohibition of trapping being that it is already trapped. This of course is relative to the size of the fish and the size of the tank.

A small fish in a large tank might be categorized as totally free or semi free it depending on the tank size. If it is semi free it would involve an issur d’rabanan. 

If a big fish is about to devour the smaller fish, is one permitted to remove the small fish from the tank? 

The answer to this question is comprised of two separate issues. The first being Tzeida – trapping. If it is difficult to fish out the fish it is a sign that they are not totally in one’s control and the prohibition of trapping is applicable. If easy to fish then it is probably called trapped and this issur would not apply.

The second issue is muktze. All animals are considered muktze and therefore removing the fish would not be possible because of muktze. One could argue that maybe when Tsa’ar Ba’alei Chayim is involved it should be permitted. The answer is that true, muktze might be waived when Tsa’ar Ba’alei Chayim is involved as we will soon see, however HaRav Shlomo Zalman Auerbach ztz”l [1] learns that natural phenomena are not classified as Tsa’ar Ba’alei Chayim.

Accordingly there is no Mitzvah of Tsa’ar Ba’alei Chayim to save a mouse from a cat. Therefore one would not be permitted to incorporate the mitzvah of Tsa’ar Ba’alei Chayim to save the small fish.

A Rav should be consulted whether it is permitted to ask a non-Jew to transfer the fish. 

If a fish dived out of the tank, is one permitted to return it on account of Tsa’ar Ba’alei Chayim? 

In other words, is one permitted to handle muktze for the sake of Tsa’ar Ba’alei Chayim? The answer is that we find conflicting opinions in the matter.

The Magen Avraham [2] learns (based on the Rambam) that muktze is not waived in place of Tsa’ar Ba’alei Chayim and in this case it would be forbidden to lift the fish back into the water. The Elya Raba [3] disagrees with the M”A and based on other Rishonim learns that one may handle muktze when Tsa’ar Ba’alei Chayim is involved. He explains the Rambam saying that the Rambam only prohibited handling muktze when other options are available.

The Chazon Ish [4] also permits handling muktze to prevent Tsa’ar Ba’alei Chayim but the Shulchan Aruch HaRav [5] only permitted it when a great loss might incur.

The Mishna Berura [6] brought down both opinions and concluded that one may definitely make use of a non-Jew in such a case.

Therefore, if your fish dives out of the tank make sure that you have a non-Jew on hand. 

If a bee (the honey maker) is disturbing me in my succah am I permitted to trap it? 

The Shulchan Aruch [7] teaches us that one is permitted to kill non-poisonous snakes and scorpions in order to save oneself from their painful bite and sting. However, says the Mishna Berura, [8] this is only true of species whose nature it is to cause harm and whose bite is painful, but insects – whose bites are not so painful – may not be killed (or trapped) and one should chase them away.

Although a bee sting is more painful than a flea or mosquito bite, yet it does not automatically sting people. On the other hand there are people who are allergic to bee stings and being stung by a bee poses a life-threatening situation.

Therefore, in normal circumstances one should remain calm and not start up with the bee and avoid trapping it. Rav Eliyahu Falk shlita presents a solution by the way of putting some honey in a teaspoon and alluring the bee out of the succah.