Just paper the walls with loop-cloth, and give the dogs Velcro shoes, and problem solved!
Just convince raccoons that there are garbage cans on Mars and we’ll have the means to get there shortly.
The gravitationally imposed size restrictions on any exoskeleton-based life are removed. Imagine how well funnel-web spiders grown to the size of cows would handle zero g. The future is more terrifying than you think.
I mis-read that as “cetaceans” at first. But then, I’ve been reading a lot of David Brin lately. Dolphins would simplify the suit problem, since they’re air-breathing, so you’d just need something to keep their skin comfortably damp. And they may or may not be smarter than octopodes, but they’re more trainable. But on the other flipper (which isn’t gripping), they don’t have many options in the manipulation department.
They’re great hyperspace pilots, though.
Still shots? Blah. how about some video?
And then there’s a weightless dog…
Apparently, also great space fighter pilots. (Because they move natively in three dimensions and think correspondingly, unlike landlubber species. And water suspension gives them extra acceleration tolerance.) At least, that’s what “Heritage” from Man-Kzin Wars XIV says.
Why? for security, companionship, and chase away possible Martian wolves.
This is what I came in here to post. One of the funniest videos. The guy shoving the white and black cat gets me every time. He’s like, “Here bro, have a cat.” and the cat is all, “Whaaaaaaaaa?”
How about gold fish? Couldn’t the just float around in bubbles without a tank? Could a goldfish even breath in a floating bubble? Or how about transporting larger fish as a food supply? Maybe catfish can float around and clean up after the dogs. 
I’m sure that in a weightless environment they could move water over their own gills without trouble. But I question whether they’re smart enough to avoid swimming out of a free-floating ball of water; without outside intervention this would likely be fatal, since they probably can’t “swim” (i.e. generate forward propulsive force) in air to get themselves back into their ball of water.
Judging from my own experience with goldfish, they’re not smart enough to stay in water even in a normal 1g gravitation field. I stopped counting the number of goldfish I’ve had jump out of a perfectly acceptable (but open-topped) aquarium.