More on sweeper tentacles

[sjpresley]

Sweeper tentacles ARE by definition used for aggressive and defensive actions.  These tentacles are capable of feeding, but their design and behavior make their purpose clear.  If a sweeper comes in contact with another coral it will usually stick and break off so that it may continue to fire off nematocysts ensuring maximum damage.

 

Corals have very refined chemoreceptive abilities that allow then to "know" what types of competitive species are nearby.  Imagine how much more concentrated enzymes and other coral secretions are in an aquarium, let alone a nano, than they are in the ocean where things are quickly diluted or swept away.

 

Therefore, corals such as Euphyllia or galaxia that regularly produce sweepers often due so because they detect the presence of competitors nearby and they are trying to "make room" for future growth.  With the elevated biochemical levels in aquaria it is likely corals "think" competitors are much closer or denser than they actually are.  Few coral species survive sweeper tentacle attacks.  You may even find them painful should you be struck.

 

To prevent sweeper formation, you must remove the competing corals that are providing the chemical cues causing sweeper formation.  Alternatively, foam fractionators may help remove the chemical cues.

 

For more information see Bornemans Coral book, the most informative book on corals you'll find.

[FamousGuy]

yep, i read a thread about a guy getting the tar stung out of him by an elegance

[Metznreef]

i've been researching sweepers alot lately too. but docorals detect cetain other species of corals as competitors? or are all other corals considered competitors to corals with sweepers?

[sjpresley]

It appears that ALL other corals are not considered competitors by particular species.  But as of yet, what competes (or "thinks" it) competes with what is unclear.  While ANY coral stung by sweepers is adversely affected, not ALL corals induce the development of sweepers.  

 

Apparantly, these interactions will need to be investigated on a species by species ( or at least genus by genus) basis.