Derbesia

[steven_dean17]

ok, how do i get rid of this stuff? I have used all suggestions that i can find. i.e. water changes weekly 15% with ro/di, good salt instant ocean, new light bulbs, no yellow light, all water test read perfectly, phosphate remover, protein skimmer(D and D typhoon, i know not great, but decent), good cleaning crew(turbos, blue legs, lawnmower), and lots of other things. I dont want to start an equipment debate or creature hoopla, i just want good ideas for combatting the problem from more experienced keepers then myself. Even the many LFS i have visted have different takes, I would like to find a fool proof method that I know would help alot of people.

[dadonoflaw]

well the test results are likely inaccurate as the algae is feeding on some kind of nutrients which are bound up so the kit doesnt read them. youu will hate this but manual removal and making sure that your nutrients are low despite the rapid absorption are the solutions. i am fighting and winning that battle right now.

[steven_dean17]

glad to hear that your winning the battle, but my question is this. if all this algee is eating up extra phosphate, at what point does it begin to starve? how exactly are you removing this green stuff. i have found removing it is fruitless due to the fact that it is impossible to remove all of it. and the chemistry of the water is exactly the same before i began croppin it. if bad water p-rams. are to blame, then when the water gets right this green goblin would die a natural death. as i firmly belive it so deserves!

[dadonoflaw]

yea i know what you mean. it is one of the more invasive species in home aquaria for a reason. do you run phosphate removal media. if you dont you should. as i remove it the nutrients start to get taken up by the macroalgae i have growing. also certain types of tangs and urchins may be worth a look if you havent looked already. there is no simple solution at this point. a combination of all these things is the only effective solution. it sucks but if you want to see through the glass you have to kill it.

[piercho]

Julian Sprung's little algae ID and control book Derbesia is a siphonous filamented green algae that is not palatable to many herbivores. It can be difficult to distinguish from other filamented (hair) green algae. IME rabbitfish grazed siphonous green algae in my tank. Some Acanthurus tangs may as well. I expect its very hit and miss with each individual fish. IME this is not preferred graze for common urchins (Diadema, boring, or tuxedo urchins). Sea slugs that graze on siphonous green algae would likely be the best bet, but these are not commonly available. For instance the "Dwarf Sea Hare". I've no experience with this slug so no experience if it might graze derbesia.

IME persistent low nutrient levels and competition from other plants is the best control for Derbesia.

[steven_dean17]

so is it safe to assume a rabbit fish would help with the harvest? how poisonous are these fish? i have a small child(2) and i will not take a chance. so maybe someone could give me another type, some sort of tang possibly? i was reading something eariler about if algae is not eating phos maybe it is the nitrogen release that is the problem. is this possible? if so what is causing nitro?

[piercho]

The doral spines of all rabbitfish are poisonious but I haven't been stung so I can't compare it to something like a bee sting. I believe its a comparatively mild sting. Each of the foxface rabbitfish I've had were very mellow; peaceful with other fish and would come right up to my hand. They never tried to spine anything or me.

As fish grazers go IME rabbitfish are good general grazers, maybe the best overall fish grazer. The mature foxface that I had would nibble the tips of Caulerpa and made quick work of red and green hair algae. But I would not bank on a specific fish grazing a specific algae. The Zebrasoma tang clan (yellow tang, purple tang, Scopas tang) are hardy and have teeth suited to graze filamented algae. They are also recommended as being hardier tangs but are usually fairly aggressive according to my references. I never had a Zebrasoma tang. I did have a Powder Brown (Acanthurus) tang for several months before I shut down the tank. It would graze filamented algae but seemed to have a preference for red algae in my tank. The Powder Brown could be mean to other grazers, for instance it would harass a large lawnmower blenny in my tank. It also a skittish fish compared to the rabbitfish.

The downside to adding a fish grazer is that it will likely require additional feeding. If it fails to graze the algae that you want it to target, the problem may get worse due to the increased bioload. Or if it does graze the Derbesia the growth of algae could shift to a different algae that it can't/won't graze, like Valonia or Caulerpa.

[steven_dean17]

thanks for the reply piercho, i will have to check more into the sting of the rabbit fish. that would keep the grass in check. i guess that would about do it for stickin my hand in the tank hugh? unless i had gloves on anyway. i would like to attack on another front as well, ground attack(snail). any favorites?

[dadonoflaw]

i understand that convict tangs eat hair algae. food and organic matter breaking down and certain foods also contain phosphates and nitrates so read the packaging.also your stocking level. what kind of fish do you have?

[steven_dean17]

i have resorted to feeding only ocean nutrition prime marine flake 2 times a week and even then only a very small amount. i have been doing this for about a month now. i dont see but a very few hit the bottom. i mean small pinches is what im talking about. i have 1-domino,1-green chromis,1-three stripe,1-lawnmower,1-gold head goby,1-skunk cleaner,1-coral banded,1-brittle star,55-blue legs,8-snails,the usual little stuff in sand and dark places(pods,worms,ect.) live rock100#s, and live sand80#s.