Hey chinn was it on mythbusters?? I saw a show on mythbusters where they were they were trying to prove whether or not goldfish have 3 sec memories, like someone said previously. They did the divider with holes in it deal, and eventually they took that route without the dividers. Their conclusion was that they must have memories longer than just seconds. I'm sure this was an example of classical conditioning much like Pavlov's dog. Don't remember their exact reasoning/conclusion, but I do know that the myth was busted.
I would also imagine that fish such as cichlids have much more of a memory/ are more apt to repond to conditioning. This would most likely be one of the reasons that over hundreds of years humans have come to be more interested in these fish as pets. If these fish have what would appear, IMO, to be larger than normal brain power, then I'm sure that they are very responsive to classical conditioning. Therefore, whether or not they have "short/long term memories" in the way we as human do, they most certainly do have some sort of inherent memory which allows them to react in a specific fashion to a certain stimuli that they have been exposed to at some point(s) in their lives. In fact, I could be wrong here, but I think that dogs don't necessarily have a memory in way that we think of memories. Instead I think that they are just much more easily classically conditioned.