What is the cause of my green goldfish tank water?

Question

I have a 10 gallon tank with 3 small goldfish in it and the water is green. I've cleaned it, put a larger filter (20-30 gal.) in the tank and declorinated it each time I add more water. Next day the tank is a green color. I've had other goldfish over the years and their tanks were never green. I've even tries algae treatments, nothing is working. I have another 2 1/2 gallon tank with tropical fish (3) and it is clear. I use the same water for both tanks which is the strange thing. Any ideas or suggestions?

The goldfish are less then 2" each and there's no algae. I've been told it's 1" of fish for 1 gallon of size. My other tank with the tropicals gets the algae ever once in a while.

Answer 1

The one inch per gallon rule DOES NOT apply to goldfish because they excrete a lot of ammonia. Your problem is that you are overstocked. Baby-juvenile fancy goldfish NEED 10 gallons PER fish, baby-juvenile long bodied goldfish NEED 20 gallons PER fish. It doesn't matter how small they are, they excrete copious amounts of ammonia.
An algea eater will not eat the free floating algae spores.
When you say you cleaned it, how did you clean it?
With that many goldfish in a dinky 10 gallon i would be doing a 20 percent partial water change daily to prevent the green water, then i would bring them back to the store or find better homes for them if unwilling to upgrade tank size.

To get rid of the green water, cover the whole tank with a blanket for atleast 4 days, do not turn the lights on, leave the filter running to provide oxygen for the fish, do not feed the fish. The no light will kill the algae spores.

Answer 2

Green water is a bloom of algae. There are of course different types of algae, but the particular one that is in your tank is a single celled, free floating algae.

There are two main causes for the presence of this algae. Excess nutrients and excess light.

The main cause is excess nutrients, specifically nitrates. This is normally caused by overfeeding and overpopulation. The three small goldfish are just barely ok in your tank, for now, but goldfish grow very rapidly, and produce a lot of waste, so they will quickly become much too big for a ten gallon tank. Doing water changes is pretty ineffective in the short run as the algae spores are already in the water, allowing it to repopulate itself quickly, but water changes do help in keeping the nutrient levels at a more reasonable level until the tank can balance itself. Keeping the nutrients low will basically starve the algae, and eliminate the problem. Live plants help tremendously in keeping the nutrient level low. They also help provide oxygen to the fish.

The other issue, which is mainly a secondary cause, is excess light. This is not only attributed to the aquarium lighting, but light in the room as well. Limit the aquarium light to 8-10 hours a day, and move the tank to a location with less sunlight.

Answer 3

Greetings

The green is suspended algae. The long term and probably best solution is to get a UV system. That will sterilize the suspended algae. You should notice the difference in 3-4 hours.

A lot of the suggestions listed by other users are good too. Cover with a blanket and turn off the light for 2-3 days will keep the bloom down. Do massive water changes (small quantities several times a day causes least stress).Keep feeding under control. Gold fish excrete a lot of ammonia! Add a large amount of plants to compete for nutrients ...

Hope this helps

Answer 4

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RE:
What is the cause of my green goldfish tank water?
I have a 10 gallon tank with 3 small goldfish in it and the water is green. I've cleaned it, put a larger filter (20-30 gal.) in the tank and declorinated it each time I add more water. Next day the tank is a green color. I've had other goldfish over the years and their tanks were never...

Answer 5

Goldfish Tank

Answer 6

Ten gallon aquariums are the hardest to keep nice. You don't mention how long you have this tank set up this is important. Aquariums go through a cycling process. During the "break in" process, nitritifying bacteria colonies are growing in your gravel bed. This is a good thing as these bacteria breaki down ammonia (toxic) and nitrites (toxic) to nitrate (harmless). Allgae is cased by 2 problems, too much sunlight & a build up of organics (nitrites and nitrates). Is your fish tank getting sun through a window? If so, closing your blinds will help. My advice is to place your fish in a bowl with their tank water. Install an undergravel filter in your tank. Please don't change your gravel as whatever good bacteria you have is living on it. Remove excess algae from the glass. Refill your tank with half old water and half new water. Never change more than 1/2 your water at once as you stress your fish and can kill them. Rule of thumb on fish tanks is 1 inch of fish per gallon of water. Don't over crowd your tank. It seems that you have loaded your tank with goldfish and you need some bottom feeders and algae eaters. They will help you keep your tank clean. Don't feel bad for your fish, algae doesn't bother them. It actually helps to clean your water by using the excess organics. You might also want to add water plants that will do the same thing but look more attractive to you. A well balanced fish tank should only need a half water change once a month to maintain proper nitrate levels. A good fish tank is a mini-ecosystem. Good Luck!

Answer 7

Wow, you are incredibly overstocked. Its creating algae, pea soup actually. That can be good (some people like it) but you are way overstocked.

The rule of thumb with goldfish (because they produce so much waste) is 10 gallons for each fish. One thing people don't realize is, goldfish can live 10-20 years. And they do grow to be very large.

You need to upgrade to at least a 10 gal. for now. The algae is because of your water quality problem, and you can't fix that in a 2 & 1/2 gal. tank.

Answer 8

Yes, you are very overcrowded. 10 gallons of water minimum per 1 goldfish. so if you address this issue, the water parameters should fall in line. But, remember this, even though algae is unsightly to us, it is not always bad for the tank and is often times, beneficial and should not be gotten rid of entirely. Some kinds of algae are a necessary part of the cycle of the tank.

Answer 9

Gold Fish Tank

Answer 10

Try turning the light off for a day or two and cover the tank with a blanket or towel. The algae is probably being caused by too much light. Also, turn their light off at night if you aren't already doing so.