sue

Could someone please tell me why my friends tank which has been set up for years. And suddenly the water levels have all shot up ammonia, nititre and nitrate levels are through the roof which has created loads of algae also 7 of his fish have died. he did a great big water change a lot more than i would have done i think he said 90% i would have only done 50% but what do i know.. he's cleaned everything in the tank and cleaned the gravel but levels are still right up.. hope somebody has some info thanks

Gunnie

It could be a lot of reasons. Something has killed the biological filter. Does your friend vacuum the gravel regularly? Have all the fish deaths occurred after the ammonia and nitrite levels became toxic?

sue

Hi Gunnie

Yes he vacuums the gravel. yes 6 of the fish died after levels had risen 1 he thinks must be old age as he's had that one for five and ahalf years. not sure what has happened in the tank for it to rise thou.

Gunnie

What I'm thinking is something that happened to me. I vacuumed my gravel in my 20 gal. long tank, but did not think about vacuuming the gravel under the ornaments in the tank. One day I came home early from work, and the tank looked like a war zone. Apparently, one of those poisonous pockets of gas had formed and seeped above the gravel killing almost all of my fish. I managed to save a few of them, but most of the tank was wiped out. Could this possibly be what might have happened? If all the gravel in the tank is not airated on a routine basis either by a gravel vac, malaysian trumpet snails, live plants or by poking the gravel with a stick of some sort, these pockets of anaerobic gases will result.

Butterfly

You say he cleaned everything in the tank. In what way did he clean everything? what type of filtration system does he have? Sorry for all the questions, but it will help us get to the bottom of this
Carol

ewolfe315

Just to add my 2 cents here. One time I cleaned all the gravel in my 55 and I got hit bad. Now I only do about 40 percent gravel cleanings at 1 time.

And as Gunnie said watch for those air pockets, I always find them in the ornaments as well.

You can also get ammonia readings just from a fish that has died and you can't see it.

John

Butterfly

Could this be a case of "Old Tank syndrome"? http://www.aquariumarticles.com/read/?art=1097
carol