Also other than the six line I would only recommend a pink streaked, possum or a small flasher of some sort. And yes if you decide to go with the six line he will most likely become a nightmare. A 29 BC will not be sufficient for any other. They will eventually stress and faint away or in a Mysteries case become super territorial and will eventually kill whatever is in that small of a cube. Sorry not trying to be a jerk but you have to remember good husbandry for your animals.