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I have algae like stuff growing in my tank. It is about .5 mm thick and green, then it turns black and comes off in big flakes. Then it starts over. A smart guy at the LFS listened to me, then went to a book, and came back and said I should put a teaspoon of hydrogen peroxide in the tank. He said it would not hurt the fish.

Is that safe? Should I do it?

(It is a 20 G tank with 8 tiger barbs and 4 corey cats. I change 20% weekly, ph is 7.6, amm/nitri/nitra=0/0/20. No meds although I put in some newimprovedcycle every month or so. I'm doing home renovations, so have moved the tank to the basement which is poorly lit. I have the fluorescent lite on a timer coming on only 4 hours per day, water temp 25'C.)

Interesting question...

Hydrogen Peroxide: "An unstable compound H2O2 used especially as an oxidizing and bleaching agent, an antiseptic, and a propellant."

Of course a teaspoon is a rather small amount in a 20 gallon tank.

If your fish all turn into blondes you may have a market for them.

Because of the irritating effect on raw flesh wounds, the medical world no longer uses Peroxide to clean wounds.

Your fish clerk may have "anticeptic" in mind when he suggests the use. Some algae is bacteria-based and therein lies the reason.

--garyroland.

Thanks Gary. Since you put it that way, I might just do a round of melafix then. At least I know the dosage. That would be simular treatment, right?

I tried that in my 29 usg for thread algae. It has worked really well. I just put a capfull in after the water change for two weekends in a row. Good luck what ever way you go.

Jan

I should clarify that I tried the peroxide, not melafix.

[span class="edited"][Edited by puddle cat 2004-08-28 13:47][/span]

Hi,

Hydrogen Peroxide has been suggested for the elimaination of cynobacteria, it has an oxidising effect on organic molecules or some such thing.

The theory is that the higher orders in your tank are protected from it's effects but the lower orders (algae) are not. A healthy slime coat should protect the fish, although the gills might be irriatated, and coatings on the plants leaves protect them.

A word of caution you need to be sure you need the peroxide - if there is not enough susceptible organic molecules for the peroxide to use up it's caustic abilities, it will irritate the fish and cause respiration problems.

Quite frankly I would be very reluctant to add anything that has the potential to harm the livestock to my tank unless I knew what I was doing. "A teaspoon" doesn't soumd like a very scientific measurement !

Good luck with whatever you choose to do and let us know how it turns out.

---

Some days you're the pigeon and some days you're the statue.

Remember that age and treachery will always triumph over youth and ability.

Wouldn't it also affect the bio-filter?

Mike

Peroxide and Melafix are two different molecules...

Melafix, a weak anticeptic, will not have the killing properties that Peroxide would.

You can try the small amount of Peroxide suggested by the clerk. It may indeed do some good.

But unfortunately, since algae has been around way before Dinosaurs roamed the earth, it will return in all its multi-colored splender.

I've found that a bacterially balanced tank and a few algae eaters will keep green algae under control but practically do nothing for blackbeard algae. Newer tanks tend to have more algae problems than well established tanks.

Mass contamination of the black/red algae can only be conquered by a complete tank breakdown, soaking gravel and all contents in 50-50 mix of bleach for 10 minutes. After that a dose of an antibiotic tab, Erythromycin, once a week, should keep the awful stuff under control.

The tab should be completely dissolved in a glass of warm water and dosed. The filter carbon must be removed for a day after dosing (24 hours) and replaced after that.

Some countries have more algae spores in their water supply than other countries, just waiting for a nice warm environment to bloom in.

--garyroland.

[span class="edited"][Edited by garyroland 2004-08-30 09:51][/span]

I've heard of Hydrogen peroxide being used for shipping... a drop or two in a bag of water with a fish releases lots of oxygen molecules... but they did caution against overdosing or even dosing multiple times because while when it ionizes in water, it also releases something else (I forget what, perhaps it forms a strong acid in a reaction with water) which can be dangerous for the fish.

I've never heard of it being used for algae control...

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We have our share of algae here in Winnipeg. The cities water supply is a lake. I'd love to get an algae eater, but ottos get pestered by the tiger barbs IMO. I've thought of a chinese algae eater maybe, I hear they are grumpy.

Thanks for the discussion, guys. I may try 5 ml of peroxide when I move the tank upstairs and the stuff gets bad again.

Hydrogen peroxide works wonders on hair algae, but dosing must be small and very precise (with a baster/dropper) as adding too much to the aquarium with rob the water of oxygen and can severely irritate/damage fish mucous.

H202 will oxidize organics including the invisible dissolve organic carbon (DOC) compounds floating around. As such, adding it directly to a tank may not have much effect. It will be 'spent' before it reaches a significant amount of the algae. Hydrogen peroxide is not a specific oxidizer. That being said, one hypothesized pathway of the barley straw inhibitory action on algae in ponds and such is the release of hydrogen peroxide. Spot treatments of H2O2 are also highly effective. This can be accomplished through turkey basters and eye droppers, as Toirtis said. I use hydrogen peroxide to clean out parts of filters that my little tube snakes can't reach.

As garyroland pointed out, it is not a permanent solution. The root nutrient imbalance should be found and corrected. I can see how hydrogen peroxide treatment might be necessary if the algae infestation were preventing you from fixing the root cause, but remember that a blackout kills algae well. In any case, if you're killing lots of algae you should be doing water changes to dilute any toxins that may be released by the vengeful little tykes.