"The horse is perfect for it."
Translation:Das Pferd ist dazu perfekt.
It seems that the German für most often translates to for but not vice versa (so an English for would require some thinking). I read that a reason for that stems from the origin of für which traces back to mean: in front of - if you give away an object for someone, it would be placed in front of him/her.
Examples where für = for would, therefore, require retaining that meaning:
[1- For a "gift" intention] These chocolates are for (für) you i.e. intended for you (so the intention is for the chocolates to be placed in front of you for you).
[2- For a quantity] She bought it for (für) 10 euros i.e. the money was set aside with the intention to be placed in front of the seller? - this is perhaps forcing it (nevertheless one can use the English upfront as in upfront cash was set aside for the seller, at least in her mind not necessarily beforehand).
[3- For a time span] I must stay there for (für) a week i.e. again with the intention of giving away something (time, upfront) to stay at a place in this case.
In cases where you use for as in for some reason or "for X" in the sense of because of i.e. essentially suggesting a reason why or a purpose like the example sentence herein (The horse is perfect for it - a reason implied), then you would not usually use für. An exception might be if you use dafür, which I believe explicitly implies for that (reason) in certain cases.
I am not sure if this is consistent. A German wouldn't think twice about when to use für vs. zu / aus etc whenever we use for in English from what I understand. Here are some more examples:
We do it for money = Wir tun es für Geld (I guess this fits  - "for a quantity" case)
We do it for fun = Wir machen es aus Spass (Notice the difference with the first example)
For example = Zum Beispiel. (for a purpose)
For your information = Zu Ihrer Information (for a purpose)
Many animals die for this reason = viele Tiere sterben aus diesem Grund (more akin to out of these reasons, the English for here is not as ,  or )
A gift for my brother = Ein Geschenk für meinen Bruder 
For sale = zu verkaufen (for a purpose)
For a given amount = Für eine gegebene Menge 
Merkwürdige Übersetzung... Dieser Satz macht keinen richtifen Dinn. Ich würde sagen: Das Pferd ist perfekt dafür. Soll bedeuten: es ist perfekt dafür geeignet. "dazu" passt nicht. So steht es auch im Internet. dazu meint: dazu gehören. Z.B. Ich gehöre zu einer bestimmten Gruppe von Leuten.
Why shouldn't it be correct? Pons gives dafuer as synonym to dazu (the 5th meaning http://de.pons.eu/dict/search/results/?q=dazu&l=deen&in=&lf=de ).