Why is the "a" used here?

Why is the "a" used here?
 

I have the following:


https://i2.lensdump.com/i/tmp0D3.png


I'm pretty sure - based on the other examples in this part of the lesson - that they are saying "the cat can see the fish" (and not "the cat can look at the fish"). So, I'm not sure why they are saying "al pez" instead of "el pez".

I guess here it's mostly because the affectionate relations people have with pets makes us treat most animals as persons, also grammatically, so this is a case of "personal a". :D
Also, in this case, although grammatically I don't think there would be any difference in saying "el gato puede ver el pez", we're using a "perception verb" ("mirar", "observar", "ver", "oír", "escuchar", etc.) and these very often need the preposition "a". :)


Some examples of using "personal a" with animals:

- ¿Le diste de comer al perro? -> Did you feed the dog?
- No puedo acariciar al gato. Soy alérgica. -> I can't pet the cat. I'm allergic.
- ¡Ya maté al mosquito que no me dejaba dormir! -> I finally killed the mosquito that wouldn't let me sleep! (Ok, not a pet, and not an affectionate sentence, but we take their being extremely annoying, as their "personality trait".) ;)

Funny thing. Up to this moment I used to think that the personal a is required for any living creature. Based on usage.

The opposite happens occasionally, too: when both the subject and the direct object are non-living things, it's common to use "personal a" to identify which one is the direct object, particularly when either one is equally capable of doing the action of the verb on the other one.