fish eating Caulurpa

[murfman]

I just finished reading this months issue of reefkeeping online and had a question for anyone or Sarah. She mentions in her article;

"Additionally, several genera of macroalgae contain toxic compounds meant to discourage herbivores from consuming them, including the toxin caulerpenyne found in Caulerpa."

I routinely feed my Tangs and Rabbitfish feather Caulerpa and Cheato that I prune from my fuge. They eat it like it was going out of style. Am I endagering my fish to this toxin?

 

[scowar]

I've read that before and have always wondered about it. I've had Caulerpa for the past two years and have always fed my Tang that stuff with no problems noticed (grape kind, not the feather kind). They love the stuff like you said. I recently removed all my Caulerpa and replaced it with Chaeto, but he doesn't like that stuff near as much.

 

[murfman]

MIne love the Cheato as well.

 

[Samala]

This abstract from the Caulerpa taxifolia conference in 2002 may shed some light on the issue. See here.

What I did not mention in the article, for space concerns, is that there is a bit of a debate about the actual purpose of caulerpenyne. While it does discourage casual herbivores, reef fish that occur in areas where Caulerpa has grown (and potentially evolved this chemical) do not seem to be affected by it.

This may be a situation of an arms race: the algae develops a weapon, but the herbivores develop a defense (or an immunity) to the weapon. So, eventually, the algae will have to step up its arms, or find another way to out fox its predators. Of course, all of this is at an unconscious level, its just happenstance that anything the alga develops or produces has a desirable (or undesirable) effect. (Thankfully!)

As you can see from the article the authors also tested rabbitfish and tangs and found that caulerpenyne was not a strong deterrent.

Chaetomorpha is not known to produce chemical defenses like Caulerpa. (Doesnt mean it doesnt have any though.. other green algae do have chemical defenses.)

So, I think your tang and rabbit are going to be just fine.

>Sarah

 

[murfman]

Thanks, Sarah!