Ok now we are getting serious expelling internal organs is NOT a good sigh that is a defense mechanism any of your other inhabitance that eat what is expelled have a good chance of dieing get the cucumber out and as much of what is expelled out of your tank NOW
FYI
Evisceration - the violent expulsion of the gut. In this case, the cuke basically expels a portion of its digestive system (guts) onto the substrate. It may be the fore or hindgut depending on the species in question, and may or may not be a serious trauma to the cucumber (Rupert and Barnes 1994). Evisceration can be induced in a variety of ways (including such factors as chemical stress, physical manipulation, crowding, etc.), and in some species, every individual in the population appears to be at the same stage of regeneration, suggesting that evisceration may be a normal seasonal phenomenon in some species (Ruppert and Barnes 1994). It is unclear why individuals go through the evisceration, but possible explanations include periods of inactivity when food is naturally rare, or the elimination of toxic wastes that have accumulated in the internal tissues (Ruppert and Barnes 1994). Whatever the cause, this? Puking your guts out? Response usually includes some or all of the digestive system (and in some cases other organs such as the respiratory tree and gonads), but is not necessarily accompanied by chemical discharge (Brusca and Brusca 1990; Ruppert and Barnes 1994). Because there is not necessarily any chemical discharge that accompanies evisceration, even a highly stressed sea cucumber that ejects its intestines may not have much of an impact on your aquarium, depending on the situation. Despite the fact that this stress response may not wipe out your tank it can poison inhabitants that eat what is discharged. It is certainly not trivial to the sea cucumber? The cuke loses its digestive capacity in the process and although it can regenerate the gut, it needs time, rest, and excellent water conditions to do so. If the cucumber was stressed enough to eviscerate in your aquarium in the first place, chances are slim that conditions are ideal for them to regenerate their gut, either.
