cucumber expelled tentacles, stomach +

Question
I have an established (2 yrs) indigenous salt water tank with DSB, fish & inverts. The other day I noticed my cucumber expelled his head - well his tentacles and a bony-type piece attached to it and what I believe is his stomach and intestines (or gonads). Both pieces are still moving and I hear at least one piece should regenerate. But I'm wondering if this is indicative of something going wrong and perhaps the cucumber is dying? I can't imagine any of the fish or crabs bothered him - they have all been living together for many months and none seem interested in the remaining cucumber parts (body and "head"). Last month I had slime algae and used UltraLife Red Slime Remover which worked great. I feed homemade food with plankton, vitamin & brine shrimp additives plus I routinely add PlytoPlankton, Zoe Marine and VitaChem for all the filter feeders and invertebrates. Could I be overdoing the nutrients? Could the Slime Remover have removed essential nutrients? All other tankmates seem fine and have vigorous appetites. How do I know if my cucumber is dying? The expelled end seems to be all healed up, but of course the cucumber is now much smaller . . .

Answer
Hi Susan. It is common for cucumbers to, in a defensive reaction, or in response to stress, expel part of their internal organs through the anus. If the animal had been in good health prior to this and whatever stress is removed then it will grow a new set of internal organs. If this has happened in a well aerated and skimmed tank, and the guts are promptly removed from the tank then nothing drastic should occur. However if this cucumber is of the wrong species, some of the animals in your tank could be poisoned and die. Some kinds of cucumbers have defensive structures, called Cuvierian tubules. If these animals are stressed, they may expel these tubules from the anus. The tubules are sticky and, in some species, toxic. However this toxin usually just distracts, irritates or sickens a potential predator in the ocean, and may result in contamination that could rapidly kill all fishes and perhaps some of the invertebrates in an enclosed aquarium. The cucumber should live to regenerate its lost parts. Do you know what species of cucumber you have? Some hermit crabs prey upon them. Do you have any? Most likely the problem with the cucumber is due to some form of stress. Something in your tank bothering it or poor water quality. Without knowing what species you have it is hard to say weather nutrition had a part to play in it because the diet varies from species to species. Some feed solely on plankton and some are strictly herbivores still others burrow into the gravel eating detritus. I don't think using the red slime remover had anything to do with this but perhaps the reason you had a red slime problem could be a part of it. Red slime algae build up in a tank that has too many dissolved organic nutrients and not enough water flow. You may want to cut back a bit on the feeding. Check your water quality and if that check out good then keep an eye on the cucumber he may be very stressed out and could be dying. Only time will tell!