Halimeda

[trainfever]

I've had Halimeda in my tank for a few months now. I know it turns white when it isnt in the light but the turns green again after being exposed to light. This morning I came down and he halimea was white with black along the edges. It's been in light all day and is still white. Anyone have any idea whats wrong? By the way, I have been dosing calcium because I know halimeda absorbs calcium.

 

[geridoc]

Sounds like it is beginning sexual reproduction. Halimeda is similar to caulerpa in this regard, and poses similar risks to tank inhabitants. It is generally assumed that the fatalities that occur after caulerpa reproduces are due to toxins from the algae, but it is perhaps more likely that the enormous oxygen demand of the reproductive cells that are released. The fish probably suffocate. You should be on alert for the release of gametes into the water, which would indicate that careful attention to adequate circulation and oxygenation is called for. I hope this warning arrives in time, since the blackening of the halimeda is a warning that sexual reproduction is only hours away.

 

[stanlalee]

since halimeda has to be rooted there is no real threat to growing out of control when this happens. You need to do a water change and keep o2 levels high when and if this happens because they deprive the water of most oxygen when they go sexual and this can kill your livestock. turning white is normal, its a calcificating algae and leaves aragonite deposits. the great barrier reef is made up mostly of halimeda deposits not stony corals. if its not doing this its an indicator you have insufficient calcium levels. Some say its a better indicator than any calcium kit. the dark green or black spotting is a sign that its going to or at least attempting to go sexual. they dont like pruning so they are easy to keep in check by chopping them short every once in a while (not too much if you want to sustain them).