Fish died - start with fresh water or keep old for cycle?

[Dexty]

Hey,

I've had this tank for about a month now - posted before, the tank is about 40 litres so very small and I had a panda moor fish in it - bad pet shop recommendation. The panda moor lasted all that time but he died today

I want to cycle the tank properly this time before adding small fish or shrimp. Shall I keep the water that is in the tank or use new water with the old filters? Or clean the filters fully too? Not sure how much the tank or filters has cycled but obviously the fish somehow died to bad water so I don't know if I should swap the water or not, it kinda feels like I am wasting a month and my fishes life if I get rid of this water but obviously I want to do it right this time so would like to know what to do

I have a ph test (shop near me doesn't sell other types) and it tests at the highest ph still, which is 7.6, it has always been this colour since I got the tank. The fish was happy active and eating until a few days ago when he got noticibly sick acting (but still looked healthy on the outside but I think I knew he would end up dying )

So what shall I do with the water?

 

[dalto]

If your fish died from water quality issues then I would keep everything the way it is.

If it had a disease you may want to be a little more cautious.

 

[Dexty]

Thanks Dalto, I don't think he had a disease, I read up on them and they all had signs of some kind. My fish just got less active and then died he looked fine on the outside though. I'll keep this water and try to do a fishless cycle now then, hopefully my next fish will stay alive. I feel so bad about my poor first fish though

 

[CCXGT]

Thanks Dalto, I don't think he had a disease, I read up on them and they all had signs of some kind. My fish just got less active and then died he looked fine on the outside though. I'll keep this water and try to do a fishless cycle now then, hopefully my next fish will stay alive. I feel so bad about my poor first fish though

Everyone makes mistakes, usually the first MAJOR mistake is what causes you to start researching for yourself and not listening to those useless LFS employees.

Right now all you need to do is wait till the tank cycles, do a big water change and you're good to go.


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[trennamw]

The beneficial bacteria are in the filter and other surfaces not the water. So ... Keep the filter but change all the water out.

It's be a good idea to pull out the filter media, and shake it in the tank water first to clean off the filter a little, while leaving the bacteria.

The beneficial bacteria are also in the gravel, but you've probably got some build up of crud in there given the fish was too big for the space. You might consider replacing the gravel.

Good job doing some research, I'd definitely do more before getting another fish. It sounds like there's more for you to understand about the nitrogen cycle and the bacteria.

If there has been no fish in there producing ammonia you might have already lost your beneficial bacteria. They need to eat, so to speak.

Good luck!


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[dalto]

The beneficial bacteria are in the filter and other surfaces not the water. So ... Keep the filter but change all the water out.

He is doing a fishless cycle, what is the point of changing all the water out?

It's be a good idea to pull out the filter media, and shake it in the tank water first to clean off the filter a little, while leaving the bacteria.

I would not do this. In my experience the bacteria colonies are extremely fragile until the tank becomes established. You should do as little to disrupt them as possible until that point. Especially in a fishless cycle where you do not have to worry about the well being of the fish.

The beneficial bacteria are also in the gravel, but you've probably got some build up of crud in there given the fish was too big for the space. You might consider replacing the gravel.

Alternatively, you could just vacuum it out once your cycle is complete.

If there has been no fish in there producing ammonia you might have already lost your beneficial bacteria. They need to eat, so to speak.

It takes a surprisingly long amount of time for this to happen.

 

[trennamw]

He is doing a fishless cycle, what is the point of changing all the water out?


I would not do this. In my experience the bacteria colonies are extremely fragile until the tank becomes established. You should do as little to disrupt them as possible until that point. Especially in a fishless cycle where you do not have to worry about the well being of the fish.


Alternatively, you could just vacuum it out once your cycle is complete.


It takes a surprisingly long amount of time for this to happen.

He should change the water because it doesn't harm the cycle, and water changes are good. It's very likely that the existing water is high in nitrates and other bad stuff. ****Almost zero beneficial bacteria lives in the water. ****

He also won't be able to tell if the tank is cycling if he can't see nitrates go up, and seeing nitrates go up is easiest starting from zero.

There is absolutely no good in keeping old water.

He should shake the solids out of the filter because it needs this periodically to keep from getting clogged.

If it takes a long time for BB to die then presumably, his surfaces in the tank and the filter have very well established colonies already.

In my experience, BB are very hardy. I have shaken the filter out at the beginning of cycles and just before adding fish and never have any issues.

Vacuuming the substrate later brings on the possibility of releasing a ton of crud, which can cause an ammonia spike.

My presumption is his tank is cycled but dirty, given that he says there was a fish that probably died from water quality issues.

Main ideas: Clean water is good. Filters without too much solids are good. Bacteria live on surfaces. Bacteria are good but buildup of detritus (solids you can see) are not. He wants to keep the bacteria from before but that's it.




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[dalto]

He should change the water because it doesn't harm the cycle, and water changes are good. It's very likely that the existing water is high in nitrates and other bad stuff. ****Almost zero beneficial bacteria lives in the water. ****

For the record, I agree that the bacteria is not in the water. That is not really the point here. However, I don't agree that water changes cannot impact a cycle. My experience, when going through the cycle in new, non-established tanks is that it is very easy to disrupt the cycle.

He also won't be able to tell if the tank is cycling if he can't see nitrates go up, and seeing nitrates go up is easiest starting from zero.

If the tank is not cycled than there should be little to no nitrates in the water. It would be interesting to for the OP to test the water and see where it is at now.

There is absolutely no good in keeping old water.

IMO, the only valid reason to change the water in the middle of a fishless cycle is if you have consumed the KH in the water and the pH is crashing or will crash or if the ammonia or nitrite levels have grown to high and are inhibiting the cycle.

He should shake the solids out of the filter because it needs this periodically to keep from getting clogged.

Once again, unless it is clogged which should be fairly obvious from the flow into the tank the more you can do to not disrupt the filter the better.

If it takes a long time for BB to die then presumably, his surfaces in the tank and the filter have very well established colonies already.

In my experience, BB are very hardy. I have shaken the filter out at the beginning of cycles and just before adding fish and never have any issues.

My experience is that what you are saying is true in well established tanks but not true in new tanks. I have no real data that can prove this other than experience going through the process many times over the years. I have always believed that this is because the bacteria is more likely to colonize in areas of high water flow so in a new tank most of the bacteria is not on random tank surfaces but in the filter. On the other hand, in a well established tank, the bacteria has had time to grow all over the place and is less subject to disruption. That is just a theory on my part though.

Vacuuming the substrate later brings on the possibility of releasing a ton of crud, which can cause an ammonia spike.

At the end of a fishless cycle you change out all the water anyway, an ammonia spike would be a non-issue during a 100% water change.

My presumption is his tank is cycled but dirty, given that he says there was a fish that probably died from water quality issues.

This is the issue we are having, I am presuming the tank is uncycled and the fish died from ammonia poisoning.

To the OP, can you test ammonia, nitrite and nitrate levels and share the readings? This would allow us to give you more accurate advice.

 

[trennamw]

Ahhhh ... Now I see. Yes, OP, the conflicting advice here is from conflicting assumptions. I'm presuming that a month with a too big fish means there's at least a partial bacterial colony and plenty of solids in your filter and your gravel.

Give it a test. If you see any nitrates, you have a partially cycled tank already. The advice on what to do next will conflict a little still, as we have varying experiences and many things aren't absolutely proven.

I lost several bettas in a tank that size, learning how to deal with pH swings in incredibly soft water. And I've changed tanks for other reasons, and set up friends, so I've cycled a small tank about 8 times in the past year, sometimes right after a fish died. And then my big tank once. I have a system that works for me, but it could have to do with variables unique to my situation.

So test it and then sift through the advice!


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