The Czech word order does not distinguish the subject from the object as does the English word order. Czech uses grammatical cases for this purpose. The subject is in nominative (pes), the object in accusative (lišku).
The Czech word order is relatively free and controlled by the topic snd comment structure https://en.wikipedia.org/wiki/Topic_and_comment . The focus - the stressed part, the new information, typically comes last.
The order we have here would be used as an answer to a question.
Who sees a fox? The dog sees a fox.
Kdo vidí lišku? Lišku vidí ten pes.
It is a perfectly natural Czech sentence.
Typically it is SVO but it is not chiseled in stone. There are situations when it can be swapped around. For a standalone sentence it is not very common but in context it is not unusual. You are putting a lot of stress on the fact that it is, indeed, the dog that sees the fox. Not the cow, not the cat, but the dog.
I think it is a common fox not a specific one (when we use then or the, to point a determinate fox) thats why before "lisku" is not a "tu lisku". The use of "ta" "to" "ten" "toho" is a specific animal, like ten pes is that or the dog. Hope helps, at least is what i understand until now jajaja
I am not a language teacher, just a native speaker. And I wasn't about to say that it is wrong, unacceptable or whatever. It simply sounds weird to me. Without context it's hard to judge, but if the question was "Kdo vidí tu lišku?" or "Co vidí ten pes?". My answer would be "Ten pes vidí lišku.", just because it sounds more natural to me. That's all. The problem actually is, that my first comment was short and has not only one exact meaning, my fault (no doubt). Thank you for interesting link, i'm gonna explore it later.