Zebra Danios swim with nose to top

[Lexiih36]

I bought some Zebra Danios yesterday. Most are dead, but I've generally figured out what happened. 2 currently remain and I guess I have a question about their behavior. Fish A is a smaller one, the most energetic and will possibly be the last to survive. Fish B is bigger and less energetic. Fish B is who I'm concerned about.

So like the rest of the deceased, he spent a good portion of the day swimming in one corner at the top of the tank with tail pointed down, nose up. He hasn't really lost coordination or his ability to float, and unlike the deceased, any time he left the surface it was either by choice, or to escape Fish A, who might also push him down. In other words, he wasn't sinking like the rest.

I'm still concerned though because unlike Fish A who is playful (or agressive, idk), exploring and seems to be adjusting pretty well, Fish B just kinda swims in slow circles at the top. Sometimes he'll go lower, but will resurface after a few seconds.

So I guess my question is whether this is normal for new fish. I've gathered that this is not normal behavior based on how Fish A acts, but perhaps he's still not adjusted and will loosen up eventually. Alternatively, he could be going the way of the rest. So far, neither has shown interest in eating.

Note: I don't actually know the genders of these fish. I don't like saying it, and make is the default gender in a patriarchal society.

 

[Deleted member 149562]

Danio do tend to consume the thin biofilm on the surface of the water, especially when the lights are off. They generally occupy the top or high mid region of the aquarium normally.

To enable a more accurate idea as to what is going on and whether it is biofilm munching, can you post photos of the fish, a full frontal photo of the aquarium and your water chemistry test results as that might also help with why the fish are behaving in that way

Thank you

 

[Lexiih36]

Danio do tend to consume the thin biofilm on the surface of the water, especially when the lights are off. They generally occupy the top or high mid region of the aquarium normally.

To enable a more accurate idea as to what is going on and whether it is biofilm munching, can you post photos of the fish, a full frontal photo of the aquarium and your water chemistry test results as that might also help with why the fish are behaving in that way

Thank you

 

[Lexiih36]

I'll have to do another test because I didn't take pictures

 

[Deleted member 149562]

From the photo it appears that there is not alot of surface water movement, which in itself can increase biofilm, but at the same time the fish do look like they are harvesting biofilm from the surface, which is quite normal behaviour.

 

[Lexiih36]

I did lower the stream because they were staying away from the side with the filter. Once I turned it down they moved over. Also here are the tests. From left to right, we have Ammonia, Nitrite, Nitrate.

 

[Deleted member 149562]

Danio are high swimmers and they really enjoy a good flow to swim against. You'll need to up the numbers so that they can schoal together.

Out of interest, what is the length of your aquarium please?

Reason for asking is that Danio are length swimmers and are not good in confined aquariums, they get stressed and irritable...which often leads to aggressive behaviour when in smaller numbers.

Sorry to be a pain but can you place the respective cards behind each test tube so that the colour of the tested water can be judged by the respective colour on the card, please.

 

[Lexiih36]

Oh and here is full frontal

 

[Lexiih36]

Danio are high swimmers and they really enjoy a good flow to swim against. You'll need to up the numbers so that they can schoal together.

Out of interest, what is the length of your aquarium please?

Reason for asking is that Danio are length swimmers and are not good in confined aquariums, they get stressed and irritable...which often leads to aggressive behaviour when in smaller numbers.

Sorry to be a pain but can you place the respective cards behind each test tube so that the colour of the tested water can be judged by the respective colour on the card, please.

I had 6. 4 of them died. I want to verify the rest won't die before I purchase more.
The length is 25.75 (it was the 20 gallon Walmart test kit. I plan to replace the lights as well because while they are strong, they're also not on a timer.

 

[Deleted member 149562]

Oh and here is full frontal

The filter really should be making miniature waves across the surface of the aquarium, this enables gaseous exchange...disolved oxygen into the water CO2 out....with that in mind, it could be part of the reason why they are sticking noses out of the water, to increase their oxygen intake. It will also break up the biofilm too, they will still harvest it but not constantly

Turn the filter up til it moves the water surface, the fish will be fine as they enjoy a good flow and will likely dart in and out of it, it won't do them any harm.

 

[Deleted member 149562]

I had 6. 4 of them died. I want to verify the rest won't die before I purchase more.
The length is 25.75 (it was the 20 gallon Walmart test kit. I plan to replace the lights as well because while they are strong, they're also not on a timer.

The nitrates appear to be on the high side tbh. That will not help any issues with the fish.

Can you repeat the test for nitrates with a sample straight out of your tap please?

Personally speaking I would not have Danio in an aquarium under 3ft long...they do grow quite long and they are more marathon swimmers rather than sprinters.

I understand that you only have the two left. I would be inclined to return them to where you bought them as the aquarium is not really suited to marathon type species....I am going to be honest with you, I would definitely take them back, get the nitrates down and look at another species, preferably one that can handle a high nitrate (if it will not reduce easily) and fish that will use all the space and not just the top quadrant like the Danio.

@Essjay can you take a look at the results on this please and advise, thank you.

 

[Lexiih36]

The nitrates appear to be on the high side tbh. That will not help any issues with the fish.

Can you repeat the test for nitrates with a sample straight out of your tap please?

Personally speaking I would not have Danio in an aquarium under 3ft long...they do grow quite long and they are more marathon swimmers rather than sprinters.

I understand that you only have the two left. I would be inclined to return them to where you bought them as the aquarium is not really suited to marathon type species....I am going to be honest with you, I would definitely take them back, get the nitrates down and look at another species, preferably one that can handle a high nitrate (if it will not reduce easily) and fish that will use all the space and not just the top quadrant like the Danio.

Well I was planning on a community tank. I wasn't only getting Danios, they were just the ones I picked first.

So I did the tap water test. I think my tests are skewed because that also detected a fair bit of nitrates. On the strip test, there was also a reading on plain tap water. I washed it out with dish soap and everything.

That explains why after doing a 75% water change those nitrate numbers were still elevated. Any recommendations for fish that can tolerate elevated nitrate levels?

This is the very first test I did 3 days after buying it. The new test looks similar

 

[Lexiih36]

It is lighter than the test from the tank.

 

[Deleted member 149562]

Well I was planning on a community tank. I wasn't only getting Danios, they were just the ones I picked first.

So I did the tap water test. I think my tests are skewed because that also detected a fair bit of nitrates. On the strip test, there was also a reading on plain tap water. I washed it out with dish soap and everything.

That explains why after doing a 75% water change those nitrate numbers were still elevated. Any recommendations for fish that can tolerate elevated nitrate levels?

This is the very first test I did 3 days after buying it. The new test looks similar

Heavier planting will do alot to bring down the nitrates to a more controlled level. Ideally the nitrates would be no more than 10ppm if you can manage that, 15-20ppm is probably the upper limit that the majority of fish will tolerate...however you want the fish to thrive, not just tolerate the water chemistry.

Hornwort, Hairgrass, Anubia and even moss balls can assist in reducing the nitrates.

I would be inclined to really go over the top on the planting, nice and heavy planting....you can always trim it back once established, that will go a long way towards controlling the nitrate levels

I think before you consider which fish to add, you might want to research plants that will help sort out the nitrate in the best and quickest way, get them established and your tests down to a more normal level...then choose the appropriate fish for the aquarium size.

 

[Essjay]

Ammonia and nitrite in the water are quick killers; nitrate is a slow killer. A high level of nitrate won't kill fish suddenly but it will take its toll over months. We now realise that 20 ppm is the highest there should be in tank water but the closer to zero, the better.


It is more difficult to remove nitrate in tap water than to stop it getting higher in the tank, which is easily achieved by plants in the tank. But there are ways.

There are filters which remove nitrate before tap water is added to a tank. I know that Pozzani nitrate filters are available in the UK, but I don't know what there is in the US. Hopefully other American members can suggest something.

Other members have had success with growing houseplants with their roots in the tank since terrestrial plants use nitrate as their source of nitrogen.