Golgfish going to the top of the tank

[SfirtenK]

Hi,

I have 6 single tail goldfish in a 150gallons tank. I have not added new fish since nov 2017. I am noticing that one of my fish has a strange behaviour, where he goes to the top of the tank in a quick mouvement to go get air every 30 sec (i made a video of him). He eats well and does not seem sick otherwise

but this strange behaviour worries me. I have a bubbler in the tank and have tested the water (no ammonia, ni nitrites and nitrates below 20 ppm). I change around 65% of the water every week.

Does anyone know why my fish does this and what can i do to help?

 

[MrsE88]

What are the other readings for the water?
Ph? Kh?
When was the last water change?

 

[TwoHedWlf]

The tank looks very stagnant, no water movement, no aeration. There's nothing disturbing the water's surface(Other than the fish) Do you even have a filter in it? Adjust it so it's disturbing the surface.

You can get a rough idea of if the tank is aerated well by looking at the fish's gills, see if they're breathing heavily. My tank next to me is a little smaller, but the fish's gills are barely moving at all.

 

[SfirtenK]

There is a bubbler but it is in the other corner so you do not see it in the video. The last water change was yesterday. There are 2 cascade 600 to filter it.
I can add a second bubbler to see if it makes a difference. Maybe it will.

The PH is usually around 7. I have not tested it lately but i use tap water so it is pretty consistent. I do not know the kh.

 

[TwoHedWlf]

There are 2 cascade 600 to filter it.

That's very little filtration for a tank that size, but at least move them so the outlet of the filter is spraying across the surface. That will aerate the tank far more than airstones will and make far less annoying buzzing while doing it.

 

[SfirtenK]

Yes, i can get a cannister filter next month. I just thought as long as i had no nitrites and ammonia it meant the filtration was fine. I will move the filters toward the surface to get more mouvement. Hopefully it makes a difference. Thanks for tour help TwoHedWlf and MrsE88.

 

[Supergeorge123]

If it is only the one than it is unlikely to be an environmental problem. It could be a behavioral thing or a physical problem relegated to that fish.

 

[CarpCharacin]

Can you measure the dissolved oxygen in the tank?

 

[Warborg]

Yes, i can get a cannister filter next month. I just thought as long as i had no nitrites and ammonia it meant the filtration was fine. I will move the filters toward the surface to get more mouvement. Hopefully it makes a difference. Thanks for tour help TwoHedWlf and MrsE88.

Oxygen is different then nitrites and ammonia. A HOB filter would help spread oxygen in the tank, Bubblers only get one area.

 

[SfirtenK]

You guys were right. I put the filters so they now blow the water slightly above the surface and create movement. My goldfish stopped going frantically to the surface every 10 seconds after a couple days.