Stinky water

[Zoe]

Hullo,
My boyfriend's tank is a 10gal planted tank, with about 12 fish (mostly tetras and a few livebearers). I clean it every week and do about 25-50% water change. However, the water is always horribly stinky! Like, sulfery-rotten stinky. The water is usually a little cloudy and when I syphon through the gravel there is a LOT of dirt that comes up. Any ideas? I know the tank is a tad overpopulated by they are all small fish. In my own tank, an 8gal planted tank, I have 10 fish and clean it weekly and it is never remotely stinky or cloudy.
I suspect the culprit is overfeeding... But I supervise the best I can and I don't really see any major overfeeding - coudl slight overfeedign cause this type of problem or is there anything else?

thanks!
Zoe

[RockabillyChick]

do you have a test kit? you should test the water and post your water perameters (ammonia, nitrite, nitrate, pH) you can take a sample of water to petco or petsmart and they will test it for you.

what kind of livebearers are they? what kind of tetras? some livebearers get rather large, like mollies, platies, and swordtails all get about 4" long. guppies stay small, and endlers are tiny.

is there a filter on the tank?
how long has the tank been setup?
do you ever wash out the filter or replace it?
how many plants are in the tank?

overfeeding could be the culprit. its much harder to underfeed than it is to overfeed.

[Zoe]

Nope don't have a testkit... We get it tested every now adn then at the petstore and its always been fine.

Guppies, and two platys and two balloon mollies (as far as I kno the balloon mollies stay fairly small?)... And white cloud tetras.

Yep there is a filter, every week I rinse the filter in some tank water to get any gunk out, and it gets replaced I'd say every 4-6 months? Whenever the sponge starts looking haggard.
The tank has been set up for 8 months or so, but only 4 months planted. There are... about 7 plants (by which I mean seven types of plants - each of them is made up of a few stems bundled together) and a handful of duckweed

Thanks And yes, my bf's mom tends to think "they're so hungry, I must feed them more!" But I scolded her al ittle and as far as I know she's reduced... I know they are tad overfed but still, to stink THAT much?

[Sprite42]

Out of 9 tanks, I have one just like this. The water always smells awful. It isn't planted, but does have live plants: Java fern, najas grass, sunset hygro, and hornwort. It only has 3 occupants: A male betta and 2 inch long baby BNs. All the water params are in line (it has been cycled for 2 years)

However, it is one of two that have gravel substrate. I am wondering if this has anything to do with it. But, the other tank does not smell at all. hmmm....

[Zoe]

Yes this tank has a gravel substrate... whereas mine has little rocks - like bigger than sand but smaller than gravel.

Zoe

[Sprite42]

That is the same kind as mine. It is smaller than the normal aquarium gravel, but bigger than sand. It is a neutral beige color...

I just finished changing the rest of my 55 gallon to sand and have some left over. I may change this tank, too! But, the plants are doing so well...