That's kind of exactly what he's telling you.
And from an emotional standpoint, it's very easy to see where you're coming from. No one really wants to accept that their guppy Bubbles isn't going to be in Heaven swimming happily in the river besides the tree of life (well, except maybe @Hans_Oddcraft. Maybe his guppy died and that's why he seems so heartless haha).
However, this assumption is a little drastic and not really fair at all to Hans Oddcraft.
From a Biblical standpoint, debatable by any means, what Hans said is simply what he believes as dictated by the Bible. Thinking about it---wouldn't our human salvation, the most important choice in our lives, be signifigantly made less special if just anything could get to heaven? We're talking about animals, not just pets.
Pets are a huge part of our lives.
But if a dog could get to Heaven without knowing salvation? We can't, and why should they? To put it simply, it doesn't make sense for animals to go to Heaven judging from what is evident.
THat's okay, and that's alright.
The fact that we may never say some of our loved ones in Heaven is neither an easy fact or a happy one.
I'll be seeing a lot of people when I finally get there, but there'll be people I won't see as well. I know it's sad, and it's okay to be sad knowing that.
But what we feel does not dictate the reality of God's Word, which says that whosoever believeth in Him (Jesus) shall have everlasting life.
It's a odd sort of question, but did any of your pets know Jesus?
The argument Hans makes is that they did not have the capacity in the first place. So, actually, it's more of a mercy to the animals than something cruel and unfortunate.
We're not saying that any animals are "not worthy". It's simply the idea that the ones we see here aren't going to be the ones we see there because God didn't mean for salvation to work that way. It'd be unfair and a lie if it did.