Fish compatibility lists are great, generalized guides that help hobbyists pick and choose their livestock based on the probability that they will get along in close quarters. That said, these lists aren’t always right. For starters, these lists don’t take anything into account other than the general behavior of a particular fish species. There is no accounting for tank size, crowding conditions, or any other areas of stress. So, two fish that show as compatible, may fight to the death the instant they are introduced. Alternatively, two fish that are not compatible may get along just fine. So, take these lists as a guideline, but not fact.