Is there anything that is the equivalent of the rubix cube for fish? Something that the fish themselves can play with? Such as a closed jar with a crab inside for an octopus. I know of a ping pong ball for an oscar but is there something more simple fish could use? Ones that aren't as mentally evolved as oscars and such. A fish such as a hoplo catfish, sun catfish, or perhaps a fire mouth.
When I had my betta Bruce, I had him in a 120ltr tank that I rearranged every water change. I partly done it to make sure there was no food trapped under the wood, but mostly because in such a small tank there wasn't much for him to do so I figured rearranging it every so often would give him (and his tank mates) new things to explore, he seemed very happy in there until the end of his days.
I think a lot of people dismiss the idea that fish need mental stimulation because its easier to ignore than provide, even though it isn't actually that hard to provide for the most part. Just my two cents..
fishhead0103666
, earlier in this thread you asked someone for proof backing up that fish need mental stimulation. Even if science hasn't proven either way, isn't it better to assume they do and potentially waste your time and effort providing it than to assume they don't and potentially risk causing fish to develop fishy depression (or the fish equivalent) by not providing? Idk, just something to think about..