White sponge killing coral?!?

[Jesskirk]

there is something white growing on the side of my coral. I think it might be harming it as it is not opening up as much as it used to. What should I do??

 

[saltyfilmfolks]

Just scrape it of with your finger or toothbrush.

 

[DancingShark]

Just scrape it of with your finger or toothbrush.

Had a few growing under my acan. They seemed to bother them so used a toothbrush to brush them off.

 

[Jesskirk]

Had a few growing under my acan. They seemed to bother them so used a toothbrush to brush them off.

Okay thanks!

 

[Brenda Wilson]

Just scrape it of with your finger or toothbrush.

What’s causing it to grow in my tank? Is there anything that will eat it?

 

[ISpeakForTheSeas]

What’s causing it to grow in my tank? Is there anything that will eat it?

To answer what’s causing it to grow:

If there’s a high level of silicates and a sufficient amount of food for the sponges (including things like Dissolved Organic Matter, bacteria, phytoplankton, and some Particulate Organic Matter), then you may see a population boom with sponges.

That said, while a few sponges can be harmful, most sponges are totally harmless:

A very select few sponges could irritate corals due to toxins they produce (these sponges compete chemically with corals), but very few sponges seem to do this. Most sponges will happily grow along the skeleton/base of corals without bothering the corals or trying to grow over them at all (sponges generally are so harmless that even the more invasive ones can generally literally grow over the top of corals, and - as long as the coral is getting enough light still - they don't harm the corals at all even when growing over them).

If you have a sponge that is harmful or just spreading more rapidly then you would like, then manual removal is almost certainly your best option here (for why, see the first quote below, for manual removal control ideas, see the other two):

Just to put this out there - the problem with using biological controls (i.e. something that eats it) with sponges is that there are a ton of different sponges, some of which look indistinguishable from others. Some of these sponges are inedible or extremely undesirable foods to some species (either because of chemical defenses* or just because of taste preferences) while being highly desirable to other species. So, even if you pull in a known sponge-eating species of fish/starfish/whatever, there's no guarantee it will eat the sponge you want it to eat. Also, many of these sponge-eating species eat other things (like coral) that you might not want them eating.

Long story short, manual removal is probably your best option for sponges until more study has been on both specific sponges and specific sponge-eaters, but you can try it if you want.

*Just as a note on the chemical defenses of sponges, many sponges produce chemicals to avoid being eaten. Some of these chemicals are more generalized, some of them are specifically anti-fish, some are specifically anti-echinoderm (starfish, urchin, etc.), etc. So, again, some things might eat one sponge but not another, and because of the whole indistinguishable thing mentioned above, the sponges that are and are not being eaten may look pretty much identical (some may be distinguished/ID'ed under microscopic investigation, others may need to be DNA tested to be distinguished/ID'ed).

Just my two cents here.

The best way I've heard to control sponge growth at this point is to use a steel straw to scrape and siphon out the sponge you want to remove. Sometimes you can create bad conditions for them and kill them off that way, but that's typically much harder and not always effective.

Some other sponge removal methods:

Other suggestions include exposing the sponge to air (obviously not a guaranteed solution, and definitely not viable for this situation); hydrogen peroxide dipping the sponge (again, not viable here); injecting the sponge with hydrogen peroxide, vinegar, boiling water, or air; microbubbles in the display; and a few more. Predation is not usually a good solution for this issue