Capped sand w/gravel and lost 10 fish

[Just Add Water3 2]

I have a 20 long, it’s been established for about 2 years. There are mesh bags at the back filled with Fluval Stratum coved with black sand. There are live Amazon Swords rooted in them. The rest of the tank is about 1-2 inches of black sand.
Recently I decided to cap the sand with black aquarium gravel as 2 years of vacuuming had depleted my sand layer to about half to one inch depth. Since adding the gravel I have lost 6 very established fish and 4 newly added fish.
I do 50% water changes every other week and have for years with no issues.
Before adding the gravel I vacuumed the tank as usual, washed all gravel and used water conditioner in the final rinse before adding it to the half full tank by hand gently as to not stir up the sand.
Have I made a grave mistake in capping my sand?

 

[gwand32 148]

I have a 20 long, it’s been established for about 2 years. There are mesh bags at the back filled with Fluval Stratum coved with black sand. There are live Amazon Swords rooted in them. The rest of the tank is about 1-2 inches of black sand.
Recently I decided to cap the sand with black aquarium gravel as 2 years of vacuuming had depleted my sand layer to about half to one inch depth. Since adding the gravel I have lost 6 very established fish and 4 newly added fish.
I do 50% water changes every other week and have for years with no issues.
Before adding the gravel I vacuumed the tank as usual, washed all gravel and used water conditioner in the final rinse before adding it to the half full tank by hand gently as to not stir up the sand.
Have I made a grave mistake in capping my sand?

Did you loose the well established fish before or after adding the new fish? Did you quarantine the new fish for 4-6 weeks before adding them to the tank?

 

[Just Add Water3 2]

After and no I did not quarantine them. I understand that can be a reason for loss, but I’m specifically asking if I harmed my tank by capping my sand before I go tearing the whole thing apart to remove the new gravel.

 

[Tomsfish12 55]

It does not sound like the way you added the gravel that it would be the problem.

 

[TwoTankAmin27]

Did you test the tank for ammonia as you started losing the fish? Normally some amount of the bacteria will be in one's substrate. So you capping the sand may have caused the bacteria living on the top 1/2 imch or so to be deprived of oxygem and this one of the things they need. The Plants will also use ammonia. But, an amazon sword is a heavy root feeder and also these will grow to about 3 time the height of a 20l. I had one outgrow a 75 gal.

Also, you do not indicate the what the 6 fish were nor how big nor did you do so for the 4 fish you added. Adding fish can cause an ammonia spike depending on the size of the existing fish v.s. the newly added ones.

In order to help you know what went wrong it helps to have a lot more info than you have provided which makes it hard to figure out what might have gone wrong. Things like water parameters, specific fish involved. dechlor used and anything else added to the tank all might be involved but we have no clue to any of this.

And or course tythe new fish might have been the cause. Information on how the fish were behaving before they died. How they dies matters as well, Did they all day in a short period of time or did they die a few at a time. More information is always better than too little when it comes to trying to diagnose what went might have gone wrong.

 

[Just Add Water3 2]

Hi, thank you for the replies. To answer your questions:
I did test for ammonia several times during the deaths of the fish. It was consistently between .25 and .5 which I assumed was due to the dead fish.

The established fish that died were:
2 diamond head tetras
2 fancy tail leopard spot danios
2, now 3 serpae tetras
The new fish that died were:
4 neon tetras

Currently I have
1 serpae tetra
2 fancy tail leopard spot danios
2 neon tetras
1 nerite snail (purchased w/ the neons)

My water parameters have been consistent and I had done 2 50% water changes and replaced the aerator stone for more turbulence.
Nitrate 10
Nitrite 0
PH 7.5
KH 180
GH 180

This morning after last nights 50% water change my results are:
Nitrate 0
Nitrite 0
PH 7.5
KH 180
GH 240

The dechlor I use during every water change is API Stress Coat +

How the fish died:
The first fish to die was 1 neon tetra, assumed it was transfer shock. Found him stuck to the HOB filter intake the next day.
After him I don’t remember the order in which they died, but they were about 1 a day, the 2 danios did die together. They had been at the top limp, then trying to swim, then just hovering, eventually found floating, one seemed a bit bloated.
The seepae tetras, one was caught at the top resting on a plant, last nights dead one was just floating and the other lying on the bottom. They were quite big, solid fish. I have had them for about 3 years (had a 10g before this 20g)
I did take a photo of the one that died last night LMK if I should post it.
The rest of the neons were either stuck to the filter intake or on the bottom of the tank.
None of the fish looked sick, none had scale issues or hot spots, nothing. They just looked normal.

Thanks for all of the help.
This morning everyone seems to be acting and eating normally except the one remaining serpae tetra - he did not eat but did come out of the plants and swim around.

 

[TwoTankAmin27]

I was hoping you had tested the ammonia soon after the 1st fish died. Both plants and microorganisms handled ammonia. Plants use it to grow among other things. The microorganisms increase or decrease in numbers based on changes in the general ammonia being produced in a tank. However, this is not instant. So what will happen if there is an ammonia spike that is not insane, is the plants grow and microorganisms reproduce. This causes elevated ammonia to become under control.

A .25 or .50 ppm reading in an established tank should be corrected pretty fast. Ammonia (NH3) in water is mostly in the form of ammonium (NH4). The latter is way less toxic than NH3. Most test kits meature Total ammonia which is the sum of the two forms. This means when we get and ammonia reading with fish and/or inverts present we then need to know how much of it is in the NH3 form.

I am conservative in the level of NH3 at which a potential danger level is reached. My red line is at 0.05 ppm. To calculate the amount in each form one needs to use and ammonia calculator online. All of this is explained here https://www.fishforums.net/threads/rescuing-a-fish-in-cycle-gone-wild-part-il.433778/ I calculated that in your water paramters (I had to assume the temp of 77F/25C) to reach 0.05 ppm pf NH3 that the total ammonia reading would have to be over 2.5 ppm

I am mentioning all of this because it is possible that when you added the new fish it caused an ammonia spike. This may have corrected mostly or entirely before the fish started to die. So when you tested the lower ppm the damage had been done and the ammonia had dropped before the fish died from the exposure.

It is also possible that the new fish brought in disease which was the culprit. The fact that all the fish did not die can be the result of different individual fish having different immunity response and were n different general health. The water changes you did might have helped to remove or eliminate a disease in the water.

We cannot know if it was a temporary fatal spike in ammonia that did the harm as you would have needed to test as soon as you detected things were amiss. So, we cannot rule that out as the cause. Similar, if a contaminant was the cause, this usually wipes out everything. So, I would doubt this was the cause.

Next, I do not normally use use dechlor at home as I have well water and do not need it. But, I am not a fan of the API Stress coat because it contains Aloe Vera. I suggest you consider changing to SeaChem Prime or any other dechlor that does not contain Aloe Vera. Of course API will disagree with this. I rely mostly on research papers for much of the information I research for fish. Almost all the studies I find on aloe vera deal with it being fed rather than added to the water.

I did find one paper which claimed using it in the water helped larvae of zebrafish regrwow their tail went a part of it was cut off. But the aloe was mostly only in the water for 24 hours, I do not trust the results as being a blessing for adding aloe ver to the water regularly or with other or more mature fish. I have also seen a paper which used aloe vera in transport water with a posative result. Again this is a shorter term exposure. When using API regularly one is adding aloe vera regularly. I figure I would rather be safe than sorry. When I do have to use dechlor on fish when I am selling at a weekend event and have to use some hotel water, I use either Prime or Amquel which do not contain aloe vera.

The fact that your fish which did not die seem to be doing OK suggests that the cuase of the problem may be gone. Since I assume you have been using the ATI product for some time, I would also conclude this was likely not the cause of the problem as it should have shown up long ago. But one problem with keeping fish is we have no idea if they are suffering harm which we cannot diagnose until weeks, months of even many years later. Unless a fish exhibets symtoms which we can see, we cannot know if they are being effected negatively in the shorter term.

I wish I could offer better help here but I do not see enough information to reach any conclusions about what went wrong only that something did. What I do know is that diagnosing fish can be extermely difficult in many cases. And we cannot catch sick fish and take them to a vet for help. This is one of the most difficult area of fish care we face and only the obvious is easy. We can see ich, wh can see fungus, we can often see external parasites. W can also see things that effect behavior. But there are many thongs that can kill fish and provide us with no clues as to why.

 

[Just Add Water3 2]

Thank you very very much for this very informative information and for the time you took to write and research it.
Does adding a new group of fish typically cause an ammonia spike? What causes it? Fear, stress?
Should I check ammonia levels after adding new fish in the future?
After acclimating them slowly to my water by way of removing theirs and replacing it with mine slowly while they are still in their fish store bag, I do net them out to transfer them to my tank to avoid fish store water.

In your opinion, how long would you wait until replacing fish?

 

[TwoTankAmin27]

Fish make ammonia. They creat most of it when they exhale and then some when they pee and poop. In addition any decaying organic matter also creates ammonia. When one adds fish it is basically a question of the mash of the fish in the tank and then the mass off those being added, The bigger the fish the more ammonia it will create.

For example lets say one has a tank with 10 adult tetras. Now if you add 3 new adults you are basically incrasing the ammonia by about 30%. But it you add 5 then that would be 50% more ammonia. The microorganisms can deal with a bit more or less ammonia but a decent amount more means something more is needed to handle the increase in ammonia this creates. An established tank with or without plants needs to increase whatever is handling the new ammonia load.

The microrganisms take time to double their numbers. under the best conditons this takes time. ANd the ones handling nitrite take longer to multiply than the ammonia ones. If doubling takes about a day or maybe two. then adding just 30% more fish mass wold take about 30% of that amount of time. So instead of a day is would be in the range of 7 -10 hours. But they start to reproduce fairly soon after ammonia rises so the ammonia levels are decreasing over time and that means they will start to help fairy soon. The only issue is how long they need to increase to the final level. it also matter how much more ammonia they need to handle. If it is 1 ppm by the time they have increase 1/2 the way toawrds the final number they are dealing with only about 1/2 of that 1 ppm. So, depending on the pH and water temp. that may serve to cut NH3 levels enough to be safe for the fish.

This is a somewhat over simplified explanation but is is basically fair accurate. There are a few variables involved which can mean it is a bit faster or slower than the above times. The key is to have a basic understanding of how it works and that alliws obe to figure out what to expect. One can add more plants for example and that means they will use more of the excess NH4 which means the less the bacteria etc. with have tio increase.

Most folks will suggest that we should not add more fish mass than about 30% of what the tank has already and certainly not more than
50%. But we could double the fish mass iver aboout 3 days in 2-3 additions safely wheras adding them all at onnce would likelt be a problem. This is what I asked ypu initially about the existing fish mass and then the mass of the new fish. We do not need to be exact here but a reasonable estimate is needed. One last observation, The nmore active fish are, the more ammonia they make.

Finally, it is batter to add too few new fish than too many. But if we use aQ tank wgich is cycled gor the fishload going into it, were can add at a measured rate since the ones left behind for a while will be safe in that Q tank for an extra day or two, whatever is the best option to use for moving them into their permanent home.

One of the hardest skills to acquire in this hobby is patience. It is usually better to move slowly unless we are dealing with issues that are harmful for the fish. It is easier to avoid an ammonia spike than it is to deal with it after it happens.

 

[Naughts32 104]

After acclimating them slowly to my water by way of removing theirs and replacing it with mine slowly while they are still in their fish store bag,

I recommend that you just float the bag for a few minutes to match the temperature then add the fish to a QT tank. Pour the fish into a net over a bucket then add them to the tank without mixing water. The bag water will be full of ammonia and you want the fish out of it asap to reduce stress. Mixing water can also increase alkalinity and oxygen which makes the ammonia more toxic. Just ‘plop and drop’.
Having said that, I suspect the neons carried disease so wait a couple of weeks without any deaths/ symptoms before adding more fish.

 

[Just Add Water3 2]

Fish make ammonia. They creat most of it when they exhale and then some when they pee and poop. In addition any decaying organic matter also creates ammonia. When one adds fish it is basically a question of the mash of the fish in the tank and then the mass off those being added, The bigger the fish the more ammonia it will create.

For example lets say one has a tank with 10 adult tetras. Now if you add 3 new adults you are basically incrasing the ammonia by about 30%. But it you add 5 then that would be 50% more ammonia. The microorganisms can deal with a bit more or less ammonia but a decent amount more means something more is needed to handle the increase in ammonia this creates. An established tank with or without plants needs to increase whatever is handling the new ammonia load.

The microrganisms take time to double their numbers. under the best conditons this takes time. ANd the ones handling nitrite take longer to multiply than the ammonia ones. If doubling takes about a day or maybe two. then adding just 30% more fish mass wold take about 30% of that amount of time. So instead of a day is would be in the range of 7 -10 hours. But they start to reproduce fairly soon after ammonia rises so the ammonia levels are decreasing over time and that means they will start to help fairy soon. The only issue is how long they need to increase to the final level. it also matter how much more ammonia they need to handle. If it is 1 ppm by the time they have increase 1/2 the way toawrds the final number they are dealing with only about 1/2 of that 1 ppm. So, depending on the pH and water temp. that may serve to cut NH3 levels enough to be safe for the fish.

This is a somewhat over simplified explanation but is is basically fair accurate. There are a few variables involved which can mean it is a bit faster or slower than the above times. The key is to have a basic understanding of how it works and that alliws obe to figure out what to expect. One can add more plants for example and that means they will use more of the excess NH4 which means the less the bacteria etc. with have tio increase.

Most folks will suggest that we should not add more fish mass than about 30% of what the tank has already and certainly not more than
50%. But we could double the fish mass iver aboout 3 days in 2-3 additions safely wheras adding them all at onnce would likelt be a problem. This is what I asked ypu initially about the existing fish mass and then the mass of the new fish. We do not need to be exact here but a reasonable estimate is needed. One last observation, The nmore active fish are, the more ammonia they make.

Finally, it is batter to add too few new fish than too many. But if we use aQ tank wgich is cycled gor the fishload going into it, were can add at a measured rate since the ones left behind for a while will be safe in that Q tank for an extra day or two, whatever is the best option to use for moving them into their permanent home.

One of the hardest skills to acquire in this hobby is patience. It is usually better to move slowly unless we are dealing with issues that are harmful for the fish. It is easier to avoid an ammonia spike than it is to deal with it after it happens.

Thank you. This is fascinating. I did not know fish exhaled ammonia!

 

[Just Add Water3 2]

I recommend that you just float the bag for a few minutes to match the temperature then add the fish to a QT tank. Pour the fish into a net over a bucket then add them to the tank without mixing water. The bag water will be full of ammonia and you want the fish out of it asap to reduce stress. Mixing water can also increase alkalinity and oxygen which makes the ammonia more toxic. Just ‘plop and drop’.
Having said that, I suspect the neons carried disease so wait a couple of weeks without any deaths/ symptoms before adding more fish.

Do you/ can you create a short term quarantine tank with like a piece of filer sponge just for new additions or do you have a QT running at all times?

 

[TwoTankAmin27]

I still have a dozen tanks and a ton of plants. This enables me to set up a Q tank and get it cycled right away. I also used to keep a bottle of DrTim’s One & Only Live Nitrifying Bacteria n the fridge for emergency use.
https://www.drtimsaquatics.com/products/one-and-only-live-nitrifying-bacteria/

It is one of the few product which contains the right microrganisms which are alive in the bottle. They are basically "asleep" but some ammonia wakes them up. When I was adding 6-8 tanks every summer essentially outside, I used to cycle the filters for them in bio-farm. I used some of the Dr. Tims along with squeezing pout the foam from cyl;ed tank filters into the farm. I was able to cycle filters for all the tanks. This saved the need to cycle them all individually. I used to sell at weekend fish events and I used cycled filters for this as well.

I did a lot of research and worked my way up to being able to do this. I would cycle the filters in anywhere from 10 -14 days using ammonium chloride and a couple of bags of crushed coral in order to have enough inorganic carbon in the farm. The microorganisms need inorganic carbon which they can get from CO2 and things like the carbonates and bicarbonates that make the KH in tanks. The KH is what hold pH levels steady. In a biofarm these get used up pretty fast and the coral insured they do not run out.

By the end of the cycling process in the farm I was adding 20-25 ppm of ammonia/day but in 4 doses of a 5-6 ppm. The ammonia gets used fast but adding it all at once would overwhelm the bacteria and archaea. I actually started out because i was setting up and redoing tanks. So if I shut down a tank I put its filter(s) into a tank and would add ammonia every for days to hold the cycle. This and the ultimate bio-farm needed frequent water changes to clear out the nitrate.

I have been at this since I set up my first tank in the end of Jan. 2001. I actually cycled my first tank with fish not knowing any better. That was the only time I did this and it also started me looking to see if there was such a thing as fishless cycling. I never cycled a tank with fish again. I started by using household ammonia with not added scents etc. I did not worry bout surfactants in the ammonia as the the amount was extremely low and at the end of the cycle before adding a full load of fish I would do a big water change and rung a large bag of carbon over night and add the fish the following day.

Somewhere along the way I learned about ammonium chloride and switched to using that instead of the household ammonia. i should say there are a number of different ways to cycle tanks including fish-in, using plants. adding a viable bottled bacteria, using established filters in several different ways. Including moving things from cycled tanks like decor, or some of the upper layer of substrate several tanks. I have tried most of these methods and finally decided on the biofarm as I usually had to set up several tanks all at the same time. But I did do a lot of individaal tank as I ramped up from 1 to 20.

I have done both tanks with and without live plants. Of my 12 tanks today I have 2 with no plants and 1 with mostly excess plants, some assassin snails and blue shrimp. It started as a tank for excess plants and then I needed to use it as well for some of the shrimp and snails which were reproducing in a few of the other tanks.

if you keep at the hobby for some time you will be surprised at how much you elearn and how good you get at it all. I have a multi0le personaity when it comes to my fish keeping. ABout ahald of my tanks became use for working with the B&W plecos and a few others and the other half of the tank are for plannted communities. Today ony 3 are for my one remaining plecos species. The other 9 are planted communities.

I am getting old and have been doing a planned downsizing over the last few years. I do not sell at events any more. However, there are a number of folks on this forum who have been at this for way longer and in a borader fashion than I have done. Some have been able to travel and see and collect to fish in their naturl habitat. I have not done this. There are member here who have way more than 20 tanks and have extensive knowledge and experience with way more species than I have. But, I only set up my first tank shortly before I turned 53. Some members here have been keeping fish for that many years or more.

However everyone here was a beginner at some point. We all started knowing little and we all made mistakes. I have wiped out a couple of tanks over the years due to igorance and or mistakes. I am also still learning the longer I keep at it.

 

[Naughts32 104]

Do you/ can you create a short term quarantine tank with like a piece of filer sponge just for new additions or do you have a QT running at all times?

Personally I just set up a small tank with filter sponge from an established filter. I use spare plants and. Bit of sand that can also be discarded after quarantine.

Others have a QT set up all the time but beneficial bacteria would need an ammonia source to maintain the cycle.

 

[gwand32 148]

I keep a quarantine tank going at all times with a group of ember tetras as the ammonia source.