What is the ruling on water that contains ornamental fish — does it become impure on account of their waste?
All praise is due to Allah, and peace and blessings be upon our master the Messenger of Allah ﷺ.
The water in a pond containing ornamental fish is pure so long as it has not been altered, for a small amount of fish waste (rawth) is pardoned and overlooked — provided it does not change the water.
It is stated in Ḥāshiyat al-Jamal ʿalā Sharḥ al-Manhaj (Vol.1/P.178): "A small amount of hair from a non-edible animal is pardoned, as is a small amount of hair from a riding animal — on account of the hardship involved in avoiding it — and likewise a small amount of fish waste is pardoned, unless it alters the water." And Allah the Almighty knows best.
I have a date farm, and the dates come in different categories, and within each category there are different sizes. How is zakāh paid on the yield?
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah ﷺ.
If the yield reaches the niṣāb (the minimum threshold for zakāh to become obligatory) — which is five awsuq (plural of wasq), equivalent to (611) kg — then zakāh becomes obligatory upon it, at a rate of one-tenth ('ushr) if irrigated by rainwater (i.e., naturally, without the use of machinery), or one-twentieth (half of the 'ushr) if irrigated using machinery/equipment.
If the yield of dates consists of different varieties, then zakāh should be paid from each variety according to its respective proportion. If this proves difficult, it is permissible to pay from a medium-quality variety [representative of the average].
It is stated in Ḥāshiyatā Qulyūbī wa ‘Umayrah (Vol.2/P.22): "Different varieties are combined together [for the purpose of calculating the niṣāb] — such as the various types of dates, the various types of raisins, and so on — and zakāh is paid from each type according to its respective proportion. However, if this becomes difficult due to the large number of varieties and the small quantity of each individual type, then zakāh should be paid from a medium-quality variety among them — neither the best nor the worst — out of consideration for both sides [the giver and the poor recipient]. If one goes to the trouble of paying from each variety according to its proportion, this is also permissible." And Allah, the Exalted, knows best.
Is fasting obligatory for a child?
Fasting is not obligatory for a child until they reach puberty. Puberty is determined by well-known signs, the most common of which are: nocturnal emission (for both males and females), menstruation (for females), or reaching the age of fifteen lunar years.
A guardian must instruct their children to fast once they reach the age of discernment, which is around seven years old, if they are capable of fasting.
How is night prayer offered?
Night prayer is offering voluntary prayer after Maghrib and before Fajr (Dawn). As for Tahajjud, it is offering voluntary prayer at night after waking up voluntarily, and for Allah`s sake as He Says (What means): "And pray in the small watches of the morning: (it would be) an additional prayer (or spiritual profit) for thee: soon will thy Lord raise thee to a Station of Praise and Glory!" [Al-Isra`/79]. Offering Tahajjud is better than offering voluntary prayer before going to bed.