Throughout my fish keeping journey over the past two decades, I have kept many species of cichlids. We know that every cichlid has its own personality. We also know that the size of the fish is not indicative of its aggression level (e.g., not all big fish are mean and not all little fish are friendly). In fact, some of the nastiest species I’ve kept are dwarf species.
Permit me to anthropomorphize with this post. So, I don’t necessarily believe in animal “happiness” and other emotions, as we (humans) define them. However, I do believe that animals can reach a state of contentedness, just as they can a state of excitement.
Anyone who follows the blog knows I’m partial to dwarf cichlids since that is what I keep, which includes shellies. If you’ve been reading for a while, you know I purchased some fish way back in the spring of this year. Included in that purchase was a group of five Telmatochromis sp. “temporalis shell.” These are wonderful little fish, but I find them to be extremely territorial for their size. This may be more a product of the small space I’ve kept them in (20g longs), but that’s a post for another day. Though the little fellas only get about 2.5″ long, they just simply don’t like being around conspecifics of the same gender. IMO, they’re more aggressive than ‘Lamprologus’ ocellatus.