The problem I see here is equating one species with another. Problems immediately arise when you compare dogs to rats to humans to whales, and so on. A dog has many orders of magnitude greater human-like qualities than a bug. If we only consider suffering in terms of the human experience, then a dog might be said to have a greater capacity for suffering. I have tried to define terms before we start wandering into vague expressions, as David Hume calls it.
I didn't mean to say that it was acceptable to provide a less than adequate environment for any animal. I merely wanted to suggest that humans project their own feelings and emotions on other animals, sometimes unreasonable so, and that it is inappropriate to suggest that a person's supposed inhumanity to a goldfish is somehow equivalent to abusing a child, or even a dog or a rat.