Fish at top of the tank

[pettygil]

Fish at top of the tank is that normal?

https://www.youtube.com/shorts/ZOVZLAYRuSg

https://www.youtube.com/shorts/H64N8R6VGdA

It's hard to get on video, but all my fish are on the top of the tank. I just did a 50 percent water change yesterday. What should I do to correct the situation?

[Aiken Drum]

Looks like there might be a lack of oxygen in the water or the fish are struggling to get what O2 is available to them into their respiratory system. The top portion of the water is where the oxygen is highest, so thats where the fish are congregating.

Some things to check.

Check your water parameters. If there is anything off with the water it could be affecting your fishes gills ability to take in O2.

Check the water temperature. Warmer water has lower ability to hold O2 than colder water. If for some reason the water has warmed up there will be less O2 than normal.

Is your filter providing good surface agitation to promote gas exchange and providing good flow around the tank? Particularly is the flow taking water from the surface down to the bottom parts of the tank? When was the last time you did some filter maintenance? Rinsed the sponges and cleaned the impeller? Maybe the flow rate has dropped through a lack of maintenance?

If you don't already have one consider an airstone to get better surface agitation and gas exchange. Remember you also need to get some flow around the tank to distribute O2.

New water is usually more oxygenated than old tank water and the action of pouring new water into the tank will oxygenate also. If you havent done a water change recently do one. Does this make a difference?

[Colin_T]

If fish are gasping at the surface, there is something bad in the water. If you just did a water change, there could be chlorine/ chloramine in the new water that is poisoning them, or something else.

Increase aeration/ surface turbulence and add another dose of dechlorinator.

Contact your water company and see if they add chlorine or chloramine to the water supply. And ask them if they have done any work on the water pipes in the area in the last few days. If they have done work on the pipes recently, they probably increased the chlorine/ chloramine in the water to make sure nothing bad is in the water. However, a normal dose of dechlorinator won't always get rid of this extra chlorine/ chloramine.

All new water should be free of chlorine/ chloramine before it's added to an aquarium containing livestock.

[pettygil]

Originally Posted by Colin_T

If fish are gasping at the surface, there is something bad in the water. If you just did a water change, there could be chlorine/ chloramine in the new water that is poisoning them, or something else.

Increase aeration/ surface turbulence and add another dose of dechlorinator.

Contact your water company and see if they add chlorine or chloramine to the water supply. And ask them if they have done any work on the water pipes in the area in the last few days. If they have done work on the pipes recently, they probably increased the chlorine/ chloramine in the water to make sure nothing bad is in the water. However, a normal dose of dechlorinator won't always get rid of this extra chlorine/ chloramine.

All new water should be free of chlorine/ chloramine before it's added to an aquarium containing livestock.

I checked the chlorine and it's 0. And the Chlormine is also at 0. I have a test kit that test the above. I just added another does of dechlorinator to the tank.
I hope that works. Thanks for your help.

[pettygil]

Originally Posted by Aiken Drum

Looks like there might be a lack of oxygen in the water or the fish are struggling to get what O2 is available to them into their respiratory system. The top portion of the water is where the oxygen is highest, so thats where the fish are congregating.

Some things to check.

Check your water parameters. If there is anything off with the water it could be affecting your fishes gills ability to take in O2.

Check the water temperature. Warmer water has lower ability to hold O2 than colder water. If for some reason the water has warmed up there will be less O2 than normal.

Is your filter providing good surface agitation to promote gas exchange and providing good flow around the tank? Particularly is the flow taking water from the surface down to the bottom parts of the tank? When was the last time you did some filter maintenance? Rinsed the sponges and cleaned the impeller? Maybe the flow rate has dropped through a lack of maintenance?

If you don't already have one consider an airstone to get better surface agitation and gas exchange. Remember you also need to get some flow around the tank to distribute O2.

New water is usually more oxygenated than old tank water and the action of pouring new water into the tank will oxygenate also. If you havent done a water change recently do one. Does this make a difference?

I just changed my fish water yesterday. Do I need to do another water change? Here is a photo of my Nitrate levels.

[Aiken Drum]

It looks on the high side. You should be able to read it better IRL than i can from a photo, but it looks around 40ppm. What does it look like to you?

If thats the day after a water change it might be a sign your tank is overstocked. Whats a normal water change schedule? How much? How often?

While 40ppm nitrate is on the high side, on its own it wont cause all your fish to swim at the surface.

[pettygil]

Originally Posted by Aiken Drum

It looks on the high side. You should be able to read it better IRL than i can from a photo, but it looks around 40ppm. What does it look like to you?

If thats the day after a water change it might be a sign your tank is overstocked. Whats a normal water change schedule? How much? How often?

While 40ppm nitrate is on the high side, on its own it wont cause all your fish to swim at the surface.

I do 50 percent water change every week.. I'm doing another water change, again, to see if that helps, with whatever is going on. Yes it looks like 40 ppm to me as well. My tank is over stocked. I'm not buying any more fish for my 20 gallon tank.

[Aiken Drum]

If your nitrate is 40ppm the day after a water change and you are already changing half the water once a week you are over stocked.

Does your tap water already have nitrate in it?

I would do a couple of 50% water changes a couple of hours apart and see if it comes down any. If your tap water is free of nitrate that should get it down to about 10ppm. Then up the water changes to 50% twice weekly, see if that keeps it lower. Longer term you may need to reduce the number of fish.

Again though, while 40ppm is on the high side, on its own it wont cause what you are seeing. Many people keep fish just fine in higher nitrate than what you have.

[Andy Sager]

Originally Posted by pettygil

I just changed my fish water yesterday. Do I need to do another water change? Here is a photo of my Nitrate levels.

You need to look at ( and show us) results against a white background. No way to tell actual value in your pic because it's on a dark background ( the table).
As Aiken stated, if your nitrate level is above 40 ppm the day after a major water change then you are either feeding too much or overcrowded ( and we have already discussed your tank being pretty well stocked. ) It comes from the end result of ammonia production. Besides from the fish's respiration, ammonia production starts with eaten and uneaten food.
EDIT: I just looked at your first video and the fish do not appear to be stressed at the surface so they may just be waiting for you to feed them. They know the food comes from above and from you so they see you coming and think food is coming. That said, if you get out of sight but can still observe your tank, watch for them to go back to the bottom or middle of the tank. If they do that, obviously there was nothing wrong. If they don't lower water level so that there is more splashing from the filter to add extra oxygen to the water.

[pettygil]

Originally Posted by Aiken Drum

If your nitrate is 40ppm the day after a water change and you are already changing half the water once a week you are over stocked.

Does your tap water already have nitrate in it?

I would do a couple of 50% water changes a couple of hours apart and see if it comes down any. If your tap water is free of nitrate that should get it down to about 10ppm. Then up the water changes to 50% twice weekly, see if that keeps it lower. Longer term you may need to reduce the number of fish.

Again though, while 40ppm is on the high side, on its own it wont cause what you are seeing. Many people keep fish just fine in higher nitrate than what you have.

I cleaned the filter and intake tube. I also did a 50 percent water change. And my Nitrate is at 0 right now. My water is at 77 degrees. That seemed to help some. I'll have to check my water everyday, to get a feeling, if I need to do a water change, or not. My Betta's tank is fine, but that tank is not over stocked. It just has one betta per tank.

[pettygil]

Originally Posted by Andy Sager

You need to look at ( and show us) results against a white background. No way to tell actual value in your pic because it's on a dark background ( the table).
As Aiken stated, if your nitrate level is above 40 ppm the day after a major water change then you are either feeding too much or overcrowded ( and we have already discussed your tank being pretty well stocked. ) It comes from the end result of ammonia production. Besides from the fish's respiration, ammonia production starts with eaten and uneaten food.
EDIT: I just looked at your first video and the fish do not appear to be stressed at the surface so they may just be waiting for you to feed them. They know the food comes from above and from you so they see you coming and think food is coming. That said, if you get out of sight but can still observe your tank, watch for them to go back to the bottom or middle of the tank. If they do that, obviously there was nothing wrong. If they don't lower water level so that there is more splashing from the filter to add extra oxygen to the water.

My fish are not a the top, like they were. There is the middle of the tank right now. But I noticed it across the room, but right now the fish seem to be fine, after I did a water change. I did put the test on a white back ground and the color looked dark . I'll have to show the test results next time on a white back ground.

[pettygil]

Fish seem to be doing ok, today. And my Nitrate is at 0 again. It was 40 ppm.
I did a water change, and now my fish are not hanging at the top of the tank.
So whatever it was, is gone. My tank is doing fine. I will keep an eye on my fish, and check my tank water daily.

[Andy Sager]

Originally Posted by pettygil

Fish seem to be doing ok, today. And my Nitrate is at 0 again. It was 40 ppm.
I did a water change, and now my fish are not hanging at the top of the tank.
So whatever it was, is gone. My tank is doing fine. I will keep an eye on my fish, and check my tank water daily.

Welcome to fish keeping.

[Caliban07]

Also check how much you are feeding. If fish eat too much dry food their stomachs tend to swell and they gulp air and release tiny bubbles in an attempt to alleviate the bloating which could look like gasping.

Also note that nitrates are the ‘smoking gun’ left behind from a high ammonia loading and ammonia is far more deadly but is gone before you can measure it to confirm