Fish Tank Water Going Green

[danb]

Hi,

Im just wondering if anyone can shed any light on why this is happening? The only thing that changed was me adding some new fish, a snail and a couple of plants; the tank already has a few plants in.

My water stats are: Amm 0 Nitrite 0 Nitrate 10 ph 7 - 180litre tank
My tank has been up and running for around 8 months

I added to my tank;
5 Rummynose Tetras
6 Beacon Tetras
2 black widows
1 flying fox
1 silver shark - gf wanted to buy this as it was going to die at the fish shop - very small less than half inch
1 large snail

Any ideas if any of this could cause the water to start turning green quickly? I do around 35-40% water change per week. Substrate is sand with rocks.

Current stocking before adding the new fish:

8 neon tetras
6 zebra danios
4 glowlight tetras
2 black widow tetras
2 rainbow tetras
2 corrys
1 gourami
1 silver shark

 

[Malt_Vinegar]

Did you add 15 fish in 1 go?

How often do you have the lights on, and what sort of lights do you use, and is the tank ever in direct sunlight?

 

[BethK]

What plants? How many? What substrate you using? You over feeding with algae wafers at all?

 

[danb]

Substrate is sand with rocks. The fish get fed once a day, all food is gone within 30 seconds, lights are on for the same ammount of time as they have always been and tank is in the same place, sometimes gets a little sunlight. T5 Lighting.

 

[BethK]

Any bogwood in there? Plants can make water greenish, it's not an issue, moss can do it too.Just abit weird, when you don't know what the actual cause is

 

[danb]

nah theres no bogwood in there. Most of the plants have now been eaten. I did the 40% water change and within a day or so it was back to green, cant see the back wall of the tank.

 

[kevinjames]

nah theres no bogwood in there. Most of the plants have now been eaten. I did the 40% water change and within a day or so it was back to green, cant see the back wall of the tank.

i have this problem around this time of year aswell. it is probably an algae bloom. this is free floating algae in the water feedin off the excess nitrates. it is caused by an ammonia spike and added light (at this time if year they is more light).

the way i get rid of it is to limit the light to the tank and limit feeding also. then i do larger water changes more frequently. if this doesnt work a full tank blackout might be advised. this would mean you getting a thick duvet and covering the tank for 1-3 days without feeding also. then a very large water change.

ive never done the blackout myself just controlled it over a longer period with water changes etc. i wouldnt worry though as it is not bad for the fish at all.

another way is to buy a uv sterilizer. this blasts the bacteria in the water and effectively kills it. they can be pricey and there is opinions that it isnt good for the immunity of the fishes.

 

[Malt_Vinegar]

I did a blackout on my main tank a few months ago (Big manual clean + water change before and after too). Best thing I ever did. I think I did 5 days.
Plants were a little upset by it, but they recovered and the algea was gone. Not yet made a return.

(I was dealing with BGA though)

 

[drobbyb]

Ammonia and light are the only things that will trigger a green water outbreak. When you added the new fish your filter bacteria had to multiply to keep up with the new bio-load. It sounds as if this small ammonia spike was all that was needed to trigger a green water outbreak. I have used and recommend the "blackout" method.

The blackout method is a cheap effective method in clearing green water. All you have to do is perform an 80% or larger water change and totally cover the tank, top to bottom, and be sure that no light gets in. Leave it this way with the lights off and do not feed for 3 to 5 days. After the blackout period, perform another 80% or larger water change to get most of the now dead algae out of the tank and resume like normal. Don't worry, your fish will be fine!

 

[danb]

Thank you, i will try the blackout method with a duvet tomorrow and let you guys know how i get on.

 

[kevinjames]

how did u get on??? looks like my green water is coming back again

 

[drobbyb]

That means you have not eliminated the cause. Have you tested your ammonia lately? Does the tank get any direct sunlight? How bright are your lights?

 

[danb]

I tried the blackening the tank out with some dark towels and while it got rid of the green murky water, i lost 2 healthy fish.

Im putting this down to them not being fed, if i were to do this again i would continue to feed the fish while the tank is blackened out and maybe an hour with the light on for feeding.

I lost a small silver shark and a small corry, the 2 smallest fish in the tank.