Zoa island question

[Lukeluke]

How far away does an island need to be to keep something like zoas from spreading to the next rock structure? Can they span a gap or as long as the rocks aren't touching above the sand they won't get to the next rock?

 

[Dcal]

How far away does an island need to be to keep something like zoas from spreading to the next rock structure? Can they span a gap or as long as the rocks aren't touching above the sand they won't get to the next rock?

yep, zoas cant "jump" and reproduce by budding. Id say a 2-3 inch gap between zoa rock and non zoa rock would be MORE than enough.

 

[Lukeluke]

yep, zoas cant "jump" and reproduce by budding. Id say a 2-3 inch gap between zoa rock and non zoa rock would be MORE than enough.

Should've included this in the OP, but does that go for something like GSP too?
2-3" was a bigger gap than I was hoping for. Might be that far from the exposed surface once sand goes in. I assume they won't try to grow under the sand to the next rock? Sand will contain them?
US quarter for scale. The two rocks on the left being the islands.

 

[Peanut]

Should've included this in the OP, but does that go for something like GSP too?
2-3" was a bigger gap than I was hoping for. Might be that far from the exposed surface once sand goes in. I assume they won't try to grow under the sand to the next rock? Sand will contain them?
US quarter for scale. The two rocks on the left being the islands.

gsp is far worse. it will grow out in strands and sheets. nothing is too far away.

 

[Dcal]

ya gsp can cross over but if youre diligent its an easy clip

 

[Lukeluke]

Must be part of its evolutionary strategy to look neat and trick you into liking it so it can take over tanks when you aren't looking.