[little dutch]

Hey folks. A friend brought his fish over for me to keep in my quarantine tank while he tries to clean up his tank. He has had the tank set up for years, live plants, and a few ancient tetras. It is a 16.5 gal tank.

He has also been fighting a very dark green algae for almost a year now. This stuff has taken over and has proven difficult to eradicate. Now that the fish are out of it, do you have any recommendations? He would like to save his plants if possible and seemed to reject my idea of pouring a bottle of hydrogen peroxide in...

 

[phil_pl]

i would pull the plants out of the tank for just a little bit and nuke the tank

 

[beaslbob]

Kill the lights.

You probably have cyano bacteria (blue-green algae) which thrive in a nitrate starved tank. Killing the lights will kill the cyano much facter than the plants and return nitrates to the system to feed the plants. Then adjust lighting to where the plants thrive and the cyano does not.


my .02

 

[little dutch]

beaslbob, he said the Algae is very dark green. I have not seen the problem for a long time, but I remember it being very dark, as dark as you can get and still be green.

I have some additional information; I do not know if this is related, but the 5 tetras he brought over for me to house all had some pretty severe fin (dorsal) damage. I watched them for a long time and they do not appear to be nipping, so that was a mystery. I treated for fungal not knowing what else to do and figuring it wouldn't hurt. Also he said his plants have taken off and are growing very fast.


Thanks for the responses, I will relay both to him.

 

[susankat]

Is the algae slimy and smelly, then its cyno, but it will also kill plants so it don't sound like it. Antibiotics will kill cyno. If he doesn't want to use peroxide to kill the algae, he can clean out as much as possible then over dose with excel or the generic glucohydride which can be gotten at a pharmacy. Leave the filter off for about an hour do a water change. The algae should start dying off. May have to do this a couple of times.

 

[Dmaaaaax]

If it is really dark green and slimey it probably is blue green algae. I would take out all the plants and put them in a dark bucket for a few days then clean the tank/filter/gravel since it is only a 16g tank.

If it were any bigger and you could confirm that it is BGA, I would change out the filter, do a 50% water change, 5 day black out followed by vacuuming of the dead stuff and another water change. For anything else, you can spot clean with peroxide or Excel and watch how long you keep the lights on during the day.

You can remove some plants and dip them into a solution of peroxide and water, but do not dip the roots, and do not keep them in the dip for more than 10-20 sec. You should start to see the algae bubble and turn yellowish.

 

[spawn]

Clean Tank

Clean tank by gently removing debris on aquarium glass with a sterile (chemical-free) scrub brush. Scrape and scrub the sides of the tank with the clean brush.
Also, do partial water changes to get rid of the tiny algae blooms that are floating in the water.

Filtration System

Do you have an older aquarium? If so, it is highly likely that the out-of-date filtration system needs complete replacement. Bio-Wheel filtration is great to combat algae problems.
In addition, it is necessary to change your filters every 4-6 weeks to maintain a clean tank.

Where is your tank?

Keep your tank away from windows. Sunlight dramatically increases the likelihood of algae overgrowth.
Since algae loves the sun, move it from this light source. Relocate your tank away from the windows.

Algaecides

You can purchase products online or at your local fish store. Algaecides can be very effective in killing algae. However, be sure to implement the other strategies. A product will help but is not a quick fix, by itself. Most brands are comparable to one another. Pick your choice of weapon.

Snails or Algae-Eaters

These aquatic friends can eat algae build-up. Snails seem to be better at cleaning up the tank. Either way, this is a natural way to get rid of algae.

Aquarium Lighting

Do not keep your aquarium lights on - all day and all night. In fact, it is beneficial to keep lighting to a minimum (for example-while feeding fish) when your tank suffers from an overgrowth of algae.
Lamps and lights are just another source that promotes algae growth. This is another excellant way to kill algae in a fish tank.

Plants

It sounds strange, but it’s true. Why have a well-planted tank? A living plant competes for the same resources as algae does. Algae also has a life of its own. Therefore, strong plants will keep algae from growing even more out of control. Amazon Sword is a nice starter plant that only needs moderate care.

Do Not Overfeed

Too much food in the water, leaves excess nutrients. Algae uses these nutrients for its growth. A small pinch of fish food a day is usually good for most average-sized tanks. Decrease or increase amount of food, according to size and number of fish in your tank.

 

[beaslbob]

Look you got the fish out of the tank, the plants are thriving, and the tank has been running for years.

Before you do all the clean up, tear everything up, and do all that work------- KISS it.


Just fill the lights for a week and see if the algae goes way.

then resume lighting with reduced duration and reduced feeding of the fish.

what happens is mature tank can become nitrate starved and the tank can rapidily switch from being plant dominated to cyano dominated because the cyano gets its nitrogen from nitrogen gas instead of nitrates.

Killing the lights kills off the cyano and returns nitrates for the plants.

At that point you have a light duration where you get cyano, and a light duration where cyano dies off (no lights). Then all you have to do is find the feeding and light duration where the plants still thrive but cyano does not.


my .02