Cucumber QT for Bang Guy

[oceanjumper]

Bang Guy,
In an other post in the Reef section you mention a filter feeding cucumber could cause a massive fish die-off. My heart froze! I just added one to the main tank, and one to my refuge two days ago.
Can you please be more specific. Are they a serious threath? Is this false alarm?
As always, thanks for the input.

 

[ophiura]

The brightly colored sea apples are the greatest risk in this case. They tend to be orange, blue, etc. While all sea cukes have the potential to release toxins, it usually requires a catastrophic event, eg, the cuke being sucked through a power head. You should cover the intakes of the PH.
The two primary species of filter feeding cukes, a small yellow and a pink/green (so they call it), are not as dangerous as the sea apples. However, they should not be placed in tanks with fish or animals that might bother or pick at them.
I think cases of poisonings are rather rare, and they tend to be related to the animal being sucked into a filter or powerhead.
I would suggest doing some searches here and on some other boards to get an idea of how often this sort of thing happens, and what they cause was.

 

[oceanjumper]

Thanks. I am pretty sure I have the knobby cucumbers. They are tannish colored with black spots (they were also "just" $7).
Are these the safe ones?

 

[ophiura]

Hold on, have they gone onto the rocks, or do they stay on the sand? If so, these are sand sifting cukes and need a fine grain sand (not crushed coral for example) in order to survive. The sand sifters tend to be much more drab in color, and often have these knobs. A filter feeder will not stay on the sand, but will go onto the rocks.
Sand sifters do not tend to be a problem, though again, if they get sucked into a power head or bothered by some sort of fish or crab, they may cause trouble. Lots of people keep them however.

 

[newreefers]

I have a yellow knobby cucumber. He lives in the rocks by day and out in the sand by night. I don't see him very often and he has not done anything negative to the tank or visa versa.

 

[bang guy]

Originally posted by OceanJumper
Bang Guy,
In an other post in the Reef section you mention a filter feeding cucumber could cause a massive fish die-off. My heart froze! I just added one to the main tank, and one to my refuge two days ago.
Can you please be more specific. Are they a serious threath? Is this false alarm?
As always, thanks for the input.
I believe Ophiura answered your question better than I could have.
I do not believe you have a filter feeding cuke based on your description. I believe you have the "mopping" type which are nearly harmless.
The danger is not in keeping the cucumbers, it's when they feel mortally threatened they can excreate a serious poison that will kill marine vertebrates.
The reason tank poisonings are infrequent is because these animals are extremely tough. The most common form of death for filter feeding cukes is starvation. They are able to digest their internal organs, so instead of the death of a large cuke killing everything, they shrink down to a very small animal before they die.

 

[oceanjumper]

Thanks all. I can breath again.
Ophiura, I have one cuke in the refuge with LS. It has been in there only two days but, so far, it has been mostly in the macroalgae and on the glass (or next to the strainer of the outgoing bulkhead).
The other cuke is in the display with CC. He crawled to the LR, stayed there for ~ an hour, and I haven't seen him since.... I read also CC was not optimal for cukes. I submitted a post on this about a week (or two) ago. Apparently, the cukes did fine. Well, if I see it again, and if think he looked better before, I will transfer him also to the fuge (can you keep two cukes in a 5 gl tank?)

 

[ophiura]

You may be more likely to see the sand sifter after the lights are out.
To the one in the fuge...
Does it have frilly, tree like tentacles that it holds out in the water? Or does it seem to shove one toward the sand with "mop" like tentacles. Typically, filter feeders seek out high "land' and good currents. Sand sifters just hang out down on the sand.