Potentially all are a risk although some species less so than others. It really comes down to the amount of water volume and type of filtration used. For the most part tiger tails and pink/black Hawaiians will not inpact a med-large sized tank. There is also spawning to be considered. While quite rare, the eggs produced by the female are extremely toxic. Once the eggs do the rounds through the equipment and burst, the toxins are quickly distributed through the water column. Sessile and mobile inverts are typically never affected, fish however would be dead within an hour or two. Sperm released by the male will degrade water quality but is not toxic. Unfortunately there is no way to tell them apart.
Just be sure if you ever consider adding one that the water paramaters are quite stable and the tank is at least 6+ months matured. An unstable or young tank will not be able to sustain them. Cukes cannot be target fed and Sea apples are even more of a concern.
Cheers
Steve