From FrugalReef

Sea Apple at Cannibal Rock in Indonesia was taken by Bradley Wm. Bowen

[edit] Statistics

• Disposition: Non-Aggressive
• Lifespan: Becomes sexually mature at 3 or 4 years and can live for decades.
• Hardiness: Requires daily attention to feed properly, but will starve for months without dieing. If well fed can live for decades.

[edit] Common Types Available

Sea Apples are Dendrochirotacea cucumbers, or more generally: sea cumbers. Dendrochirotacea cucumbers are filter feeders. They have very large feathery feeding tentacles and will attach themselves in areas of high flow to extend their tentacles in. For information on other types of cucumbers, see Sea Cucumber.

[edit] Reef Safety

Dendrochirotacea Sea cucumbers are considered by many to not be reef safe. However, with proper precautions, many people keep them without problem. If a sea cucumber becomes badly injured it may release toxic compounds. Filter feeding cucumbers are usually much more toxic than their deposit feeding brethern. Care needs to be taken to make sure they can't get sucked into pumps or overflows. You may wish to take additional measures to hedge against a possible toxin emission by using activated carbon filtration (And keeping it fresh) and a high level of protein skimming. See below for more information on sea cucumber toxicity.

[edit] Feeding

Dendrochirotacea cucumbers such as sea apples are filter feeders. These need to be dosed with phytoplankton at least once a day. Recomended twice a day. They will not eat brine shrimp. Even the youngest brine shrimp are too large for them to consume.

A sea cucumber that is feeding properly will have it's feeding tentacles deployed and will slip one into it's mouth about once a minute to suck the phytoplankton off of it. If it's tentacles are not deployed, then there is a serious problem with either the flow rate or the food provided. A hungry sea apple will deploy it's tentacles within seconds of phytoplankton being introduced into the tank.

[edit] Sea Cucumber Toxicity

Sea cucumbers have a reputation for killing tanks when they become injured. If a sea cucumber is badly injured or extremely (It's life is threatened) stressed it will release a toxin into the water. The danger of this toxin varies widely by species. The colorful filter feeders such as sea apples in general are much for toxic than the more drab sand feeders.

The animals are much more robust than they appear, and generally toxin release can be prevented by making sure the animal doesn't get sucked into a power head or unprotected overflow. Use strainers to cover the intakes on pumps and power heads if possible. When your hand is placed over the intakes on these strainers you should not feel any suction. These precautions are important with all mobile invertebrates, and not just cucumbers. If these precautions are taken it's reported that toxin emission becomes a very rare event.

In addition, you may wish to hedge against a possible toxin emission by utilizing protein skimming and activated carbon in your filter.

If a sea cucumber is injured or dies in your tank, remove it immediately and begin water changes. Adding some carbon into your sump or filter is probably a good idea as well. If you have one on hand, a protein skimmer will help as well.