A familiar must be bound with an "appropriate" Technique and Form. Multiple Techniques and/or Forms may be appropriate -- e.g. both Animal and Vim are appropriate for all magical animals. The corebook suggests that looking at what the familiar "does" is a good point to figure out the appropriate Techniques: e.g. builders (like beavers) are associated with Creo, whereas destroyers (like venomous serpents) are associated with Perdo.
I was wondering whether it would make sense to bind with Creo a familiar that is the "perfect" specimen of its species. The rationale would be that Creo is not just about creating something, but also about perfecting it. It sounds a bit strained, but not entirely unreasonable to me.
IIRC a familiar (beast of virtue) is a perfect example of its kind. So a perfect venomous asp would be associated with PeAn or something like that. Perfect for its kind does not necessarily mean Creo in my book A perfect destructive animal would be associated with perdo, and a perfect inquisitive animal with intellego. otherwise since familiars tend to be animals of virtue all (most) of them would be associated with creo.
Agree with Xavi, all creatures of the magical realm are more perfect versions the base beastie. Although I can see the rationale, creo = more perfect, magical animal = more perfect, I think this thinking would add creo to the animal and vim arts being appropriate and it would probably be best to avoid adding too many automatically appropriate arts.
I go one step further. A magi can usually only forge a bond with a familiar if their highest TeFo is appropriate to the animal.
So if your highest TeFo is Creo Terram then you have to track down a magical animal that creates, mends, or perfects, dirt, earth, metal, or some such.
Could be if you need it to be. While not covering all possible familiars, I would think it would certainly cover a creature created by magic. Instead of spending seasons looking for the needed creature, research a ritual to make it in your lab.....
Remember that the familiar has to respect you, and you respect him. it is not a pet, it is your family. Don't know if the monster of Frankenstein would fit that description. Yet, it might.
A perfect destructive animal would be associated with perdo, and a perfect inquisitive animal with intellego. otherwise since familiars tend to be animals of virtue all (most) of them would be associated with creo.