Is Eating Testicles Permissible?
Question

I have some questions having to do with some types of food:
1. Is it permissible to eat the testicles of halal-slaughtered animals, such as goats for example?
2. Is it permissible to eat shrimp?
3. Is it permissible to eat crabs?
4. I heard that there are seven animals that it is not permissible to eat; can you clarify?
Praise be to Allah.Are testicles permissible?
It is permissible to eat the testicles of lawfully-slaughtered animals, as there is no evidence to suggest that it is not permissible, and the basic principle is that things are permissible. 
It says in Al-Mudawwanah:
“That which may be included with meat, such as fat, liver, stomach, heart, lungs, spleen, kidneys, neck, testicles, feet, head and the like, comes under the same ruling as meat.” (Tahdhib Al-Mudawwanah by Al-Baradha`i, 1/93) (See also Mawahib Al-Jalil, 6/204) 
The Standing Committee was asked: 
Is it permissible to eat the testicles of an animal that are cut off whilst it is alive? 
The committee replied: 
“It is not permissible to eat anything that has been cut from an animal that may be eaten, when it is alive, such as the testicles, fatty tail, and so on, because that comes under the ruling on “dead meat”, because the Prophet (blessings and peace of Allah be upon him) said: “Whatever is cut from an animal when it is still alive is `dead meat.’” (Fatawa Al-Lajnah Ad-Da’imah, 22/501-502) 
This implies that it may be eaten if it comes from an animal that has been slaughtered in the prescribed manner. 
However, some scholars regarded it as disliked to eat them, because this is something that people usually find off-putting. 
It says in Al-Mughni (3/296): “That part of the animal is not regarded as good to eat.”
Az-Zayla`i (may Allah have mercy on him) said in Tabyin Al-Haqa’iq (6/226): 
“It is disliked to eat the vagina, testicles, glands, bladder and gallbladder of sheep, because they are things that people find distasteful and they dislike them.” 
Is eating crab permissible in Islam?
The basic principle with regard to sea creatures is that they are permissible to eat , because Allah, may He be Exalted, says (interpretation of the meaning):
“Lawful to you is (the pursuit of) water game and its use for food - for the benefit of yourselves and those who travel.” [Al-Ma’idah 5:96]
Al-Bukhari (may Allah have mercy on him) narrated (5/2091): 
“`Umar said: Its “game” is that which is hunted and caught, and its “food” is that which it casts up (onto the shore). Abu Bakr said: That which floats is permissible. Ibn `Abbas said: Its “food” is its “dead meat” (that which dies without being slaughtered in the prescribed manner), except that which has started to rot. Shurayh, the companion of the Prophet (blessings and peace of Allah be upon him) said: Everything in the sea is (regarded as if it was) slaughtered in the prescribed manner.” 
And the Messenger of Allah (blessings and peace of Allah be upon him) said concerning the sea: “Its water is a means of purification and its ‘dead meat’ is permissible.” (Narrated and classed as authentic by At-Tirmidhi, 69. Also narrated by Abu Dawud, 83; classed as authentic by Al-Albani in Al-Irwa’, 1/42) 
And the Prophet (blessings and peace of Allah be upon him) said: “Whatever Allah has permitted in His Book is permissible; whatever He has prohibited is prohibited; and whatever He has remained silent about is pardoned, so accept Allah’s pardon, for Allah is never forgetful.” Then he recited this verse (interpretation of the meaning): “and your Lord is never forgetful.” [Maryam 19:64] (Narrated by Al-Bayhaqi, 20216; classed as authentic by Al-Albani in As-Sahihah, 2256) 
Based on the above, eating shrimp and crab is permissible and there is no reason not to eat them, because of the general meaning of the evidence which indicates that everything caught from the sea is permissible. 
But if it is proven that any of these things are toxic or harmful to the one who eats them, then it is prohibited to eat them, because of the harm that it may cause, not because it is prohibited in and of itself. 
Number of prohibited animals in Islam
We do not know of any text that limits the number of prohibited animals to seven. Moreover, there cannot be any such limit if we examine the texts. The texts say that pigs, any wild animal that has fangs, any bird that has talons, tame donkeys and scavengers are all prohibited. 
The Prophet (blessings and peace of Allah be upon him) instructed that five animals are to be killed , namely: crows, kites, rats, scorpions and vicious dogs.
For more details, please refer to the following answers: 231261 , 2841 , 85534 , and 70320 .
And Allah knows best.