New Tank, Fish Stay At Top

[AshFish]

Hello. We recently got a 25L fish tank with a heater which is being kept at about 26c, and a filter. We first tried 4 cardinal tetras but they died in about 10 minutes. They all kept hanging out at the top of the tank. We had set up the tank about 3 or 4 days before we got any fish. We took ammonia readings, Carbonate Hardness, General Hardness, Nitrate, and Nitrite readings before we put in any fish. We also added 'love fish Filter Boost' to establish the bacteria. (I also should mention we have some moss balls and a few other plants in the tank and have been leaving the light on for 12-15 hours a day and turning it off at night)

Anyway the first four fish died so then we went and got 6 harlequin tetras. We have had them about 15 hours? And they also were swimming to the top of the tank. We noticed though that if we took water out of the tank and then put it right back in they seemed to swim around a bit lower for a while, 20 or 30 minutes. So we thought maybe there was somehow an oxygen issue. I went out and got an air pump just to rule out that possibility but they are still swimming at the top. (Also the fish haven't eaten anything since we got them, tried one flakes worth of food and none of them touched it)

 

[Lunar Jetman]

So firstly, IMHO the only fish I'd put in a 25l tank is a Betta because its really too small for much else.

If the issue is oxygen you're better off changing the water as all an air stone really does is agitate the water. It won''t really put much oxygen in. You're better off carrying out water changes.

When you say you've taken readings of the water, what are they? For fish to die in 10 minutes it suggests that there's something quite toxic in the tank.

How often have you been changing the water in the tank and how much each time?

the first thing I'd do if you still have fish in there is to change at least 50-60% of the water straight away and keep doing so on a daily basis until this has all been resolved.

If you post up the water parameters that might give us a better idea what is going on with your tank.

Also as an aside, i'd only have the tank lights on for 8-9 hours a day not 15.

 

[AshFish]

Thanks,

We don't plan to really get any more fish. The fish guy told us to start with these 6 and that we could add in maybe a few more other fish later. The first fish we got from the pet store (the ones that died), and the ones that are still alive we got from this fish guys store.

PH was 7.2. The Carbonate Hardness was 6. General Hardness was between 7 and 14. Nitrate and Nitrite were 0. Ammonia was 0. Since we only set up the tank last Saturday or Sunday we did not change a lot of the water. Maybe 5 - 10 liters in total. (Part due to when we acclimated the fish putting water from our tank into their bags) And then some because we were worried about the oxygen. We thought we should turn the lights off longer but worried about what if the plants produced CO2 and killed the fish. (Sorry if this all sounds ridiculous) Basically what we have just been doing for the past 24 hours is scooping up the water and dumping it back into the tank hoping that it would give it oxygen because we were worried since the tank is new and the fish have only been in it less than 24h that the good bacteria wont have time to grow if we change a lot of water.

About the fish that died, they acted the exact same as these fish did at first, going straight to the top but we did not change any water with those fish and we sat them in the bag mixing in our water for probably an hour before we put them in our tank. With the second set we spent a lot less time mixing in the water, and after we dumped out some water and put new water in they briefly got lower in the tank. Then we read about not getting new water but continuing to just pour water from up higher back in.

I will make sure to keep the tank lights on for less time. Thanks.

 

[Colin_T]

Hi and welcome to the forum

Have you got a filter on/ in the aquarium?
Is it run all the time?

The fish are either being poisoned by something in the water, or are suffocating. If you have a filter on the tank and it is run continuously, then there is a chemical in the water that is poisoning the fish.
What did you clean the tank, gravel and everything else with when you got it?

If the fish have been poisoned the best thing to do is a 75% water change each day. Make sure any new water is free of chlorine/ chloramine before it is added to the tank.

If you have a power filter you can add some carbon to the tank and that will absorb chemicals from the water.

Make sure you use a clean bucket for the fish that has not had any chemicals or cleaning products in.
Make sure you don't have any creams, grease, perfume, or chemicals on your hands when working in the tank.
Make sure there are no perfumes, hair sprays, deodorant, air freshener, paint, smoke or any other fumes in the room with the fish.

 

[AshFish]

We have a Ciano Aquarium 25 Litre which came with a filter and it is always running. (Ciano FC 40 I believe ) "Endowed with high performance 3 Stage filtration system to maintain crystal clear water for as long as possible" (But I am not sure specifically what filter it is or it has carbon/ if we can put carbon in it. It had foam in it and either "Water Clear Chemical filtration"

When we set up the tank we washed the plants off in the sink and washed the gravel in the sink in a strainer (Possibly we didn't wash them good enough?), and the decorations in water only. We filled the tank with water from a measuring thing we use for food so it possibly had soap on it. possibly we did not clean the tank itself enough?

I will try to change more of their water then, we were just worried it would not be safe to do so. We mostly have been worried about 'doing too much' and stressing the fish out.

Thanks

 

[Colin_T]

Did you add a dechlorinator (water conditioner) to remove chlorine form the tapwater?

I can't find any images of the filter. If you can take a picture of the filter we will have more idea of what it is.
And have a look in the filter and take a picture of any filter materials in it.

 

[AshFish]

We did add some things to the water. Tap safe when we add new water, and the filter boost at the beginning / every other day. I will attach a picture with the chemicals and test strips we have been using.

Filter:
It looks like the filter under the technical information on this site: http://ciano.pt/en/produto/cf40/
It does have some stuff growing on it (not sure if that means anything)

The bottom is some foam / mesh and it came with a little cartage which we put in the middle near where the water comes out. I will try and take it apart and get some photos of the material inside.

 

[Colin_T]

It looks like a type of internal power filter. If one of the filter media is a black granulated substance, that is carbon and will absorb chemicals from the water.

You should have the filter outlet blowing across the water surface to maximise the oxygen levels in the water.

The white stuff on the glass and things in the tank is usually bacteria or fungus and will normally go after a few weeks.

Milky cloudy water is caused by bacteria feeding on uneaten food. Doing a 75% water change and gravel cleaning the substrate each day for a week will normally fix that.

I assume the Tap Safe is a dechlorinator that removes chlorine from tap water. That is fine.
Filter Boost sounds like a filter bacterial supplement that is sued to get the beneficial filter bacteria growing faster. that is also fine.

At this stage I would just do daily water changes and increase aeration/ surface turbulence.

 

[Essjay]

The manual says the filter contains a Water Clear cartridge and a foam, with a Bio-Bact cartridge as optional. Further googling says that the Water Clear cartridge contains activated carbon.


But I have to agree with Lunar Jetman that this 25 litre tank is too small for the fish you have put in it.

 

[AshFish]

It looks like a type of internal power filter. If one of the filter media is a black granulated substance, that is carbon and will absorb chemicals from the water.

You should have the filter outlet blowing across the water surface to maximise the oxygen levels in the water.

The white stuff on the glass and things in the tank is usually bacteria or fungus and will normally go after a few weeks.

Milky cloudy water is caused by bacteria feeding on uneaten food. Doing a 75% water change and gravel cleaning the substrate each day for a week will normally fix that.

I assume the Tap Safe is a dechlorinator that removes chlorine from tap water. That is fine.
Filter Boost sounds like a filter bacterial supplement that is sued to get the beneficial filter bacteria growing faster. that is also fine.

At this stage I would just do daily water changes and increase aeration/ surface turbulence.

Thanks,

I'm not sure quite how to have the filter blowing at the water surface. We can't angle the jets and we weren't sure if we should lower the water in the tank to that level. What I did for now is changed 25% (6l) of the water when I took the filter out. (Made sure it was the same temp as the tank and added the Tap Safe.

The manual says the filter contains a Water Clear cartridge and a foam, with a Bio-Bact cartridge as optional. Further googling says that the Water Clear cartridge contains activated carbon.

And thanks for letting me know about the carbon.

They are not at the top anymore :O (Although I don't know if this is permanent or temporary.)

Would like to take the air pump out if it isn't required and can be harmful but left it for now since they are no longer on the surface.

Thanks for all the knowledge.

 

[Essjay]

Can the spray bar - the tube with little holes that the water comes out of - be rotated so that the water comes out pointing 45 deg towards the surface?

 

[Colin_T]

You should be able to raise the power filter so it is closer to the surface.

If you have an air pump blowing bubbles into the tank, the aeration from the bubbles will be beneficial to the fish. The air bubbles will also mean you don't need to have the filter outlet by the surface because the bubbles will create surface turbulence instead.

The surface turbulence from the bubbles will allow excess carbon dioxide (CO2) to come out of the water and oxygen (O2) to get into the water.

 

[AshFish]

The manual says the filter contains a Water Clear cartridge and a foam, with a Bio-Bact cartridge as optional. Further googling says that the Water Clear cartridge contains activated carbon.


But I have to agree with Lunar Jetman that this 25 litre tank is too small for the fish you have put in it.

To be honest we got the fish & quantity that the fish guy suggested after we told him the tank size. I feel pretty bad because I didn't know it would be too small for them but I very much appreciate all the help and knowledge. Will this be alright if we don't get any more or should we consider giving them back? or to someone with a bigger tank?

Can the spray bar - the tube with little holes that the water comes out of - be rotated so that the water comes out pointing 45 deg towards the surface?

I tried to rotate it and couldn't I'm guessing its glued or I am just not very strong.

You should be able to raise the power filter so it is closer to the surface.

If you have an air pump blowing bubbles into the tank, the aeration from the bubbles will be beneficial to the fish. The air bubbles will also mean you don't need to have the filter outlet by the surface because the bubbles will create surface turbulence instead.

The surface turbulence from the bubbles will allow excess carbon dioxide (CO2) to come out of the water and oxygen (O2) to get into the water.

Thanks

 

[Colin_T]

I would leave them there but that is just me. Everyone else is going to tell you to return them. They are small fish that don't race around the place so should be fine once the water is sorted out. If you want to return them that is fine. You could contact the pet shop and ask if you could return the tank and upgrade it to something a bit bigger (40 litres +), then you could put the harlequins in the bigger tank and use that instead. If the pet shop is willing to do this, you would take fish and water and put them in a bucket with the airstone bubbling away. Wash the tank out with water and drain and dry it. Then swap it for the new tank and use the water with the fish to fill up the new tank, and then top the new tank up with dechlorinated water. Generally the bigger the tank, the more fish and more variety of fish that you can keep.

 

[TallPaul]

I'm relatively new to fish keeping myself but I wouldn't recommend anything other than a single betta in a 25 litre tank.

New fish keepers often make the critical mistake of buying a small "starter" tank. The problem is that any chemical changes to the water can happen extremely quickly. In the space of a few hours the water can become toxic, especially if it is over stocked.

For the incident of fish dying then I would wonder if there was any chemical residue present on the inside of the tank.

Cardinal tetra isn't a good choice for a new tank, they would prefer a more established tank. Harlequin rasbora should have been tougher, danios or guppies also can tolerate changing conditions more than other fish.