Sorry, another long post. It is the only way I know how.......
Acclimation for FW fish is greatly overrated. For those of us who get fish shipped to us, acclimation can mean losing fish not saving them. We do what is called plop-and-drop. Open the bag, pour the water and fish into a big net over a bucket and then add the fish to the tank.
Most fish can live in a range of parameters. You never seen it stated anywhere that they must be in exactly 78 F water or only in pH 7.2 for example. Some fish actually thrive on change, think of seasonal spawners where the conditions between the two seasons are very different and the changeover happens quickly.
Further, I have looked for papers on acclimation of fish. These are not so easy to find. Most studies which look into what is bad for fish also have to kill them. The statistic used for a lot of the is how long something takes to kill half the fish in the trial. The best research I have found deals with temperature. The goal is to know at what high and low temps the fish are going to die and then how they behave as they approach these temperatures.
However, these sort of studies do tell us about acclimation because in most case the fish to be used in the experiment are acclimated in the lab before the experiment begins. And these acclimation times vary from a week to a month. That is a big clue about how long acclimation may take. I did find one temperature study which also asked the question, what if we observe fish behaving such that we know they are going to die shortly because the water it too hot or too cold, can they be saved? The answer was yes, and the way was to move them back into their normal temperature range ASAP. No acclimation!!!!
I did find one study dealing with acclimating zebra danios (not using a formal citation, sorry).
Gill membrane remodeling with soft-water acclimation in zebrafish (Danio rerio)
Abstract
Little is known regarding the ionoregulatory abilities of zebrafish exposed to soft water despite the popularity of this model organism for physiology and aquatic toxicology. We examined genomic and nongenomic changes to gills of zebrafish as they were progressively acclimated from moderately hard freshwater to typical soft water over 7 days and held in soft water for another 7 days..........
From https://journals.physiology.org/doi...jkey=0e0761615a8a2d19ae1330103710509d7e03eadb
It took days for the physiological changes which accompany true acclimation to manifest.
As for your stocking, yes you can do it over a few days. However, try to add the bulk during the first 24-48 hours. Stores can have healthy tanks one day and not the next. They do not normally acclimate fish and want to sell them quickly. Also, the more fish you have at the outset, the fewer potential cycling related issues you can have with later additions which take much longer to acquire.
Think of it like this greatly simplified example. A tank when fully cycled can hold 10 fish. But one only adds 5 fish and then waits a month. The bacterial colony dies back to accomodate those 5 fish. Now if one added the other 5 fish, the bio load is doubled and there will be ammonia and nitrite spikes. So one would need to add new fish slowly. One new fish would increase the bioload 20% and two would be 40% etc. One the other hand, if one started with 5 fish they could add two then three for example with fewer worries. And if one started with 7, they might even get away with the next 3 all at once.
Why many do not acclimate fish shipped in. It has to do with chemistry.
So, the fish have been adequately purged so they will not poop much if at all in transit. They have been properly bagged in clean water. And away they go. What is now happening in the bags?
Every time a fish exhales it excretes both ammonia and CO2. The CO2 will create some acid which will start to drop the pH in the bag water. This is a good thing because as the ammonia level is building up, the lower the pH in the water, the more of the ammonia that will be in the less toxic form of ammonium, NH4.
About a day later (or more) the fish arrive. There is a decent amount of ammonia and CO2 now in the water but the ammonia is NH4 and not yet a worry. But, when the bag is opened what will happen. Fresh air goes in and the excess CO2 in the water to comes out. This lets the pH go back up. And that means some of the NH4 will turn into the very toxic NH3 form which is ammonia and which harms fish in concentrations as love as .05 ppm. The longer the fish is in the bag, the more toxic the water becomes. And this happens pretty fast.
Most fish, if healthy, can withstand changing conditions up to a point. I normally want to know in what parameters fish I am getting were being kept. I also keep mostly fish which will thrive in my well water and I Q all new fish. A month for tank raised and three months for wild caught.
Acclimation for FW fish is greatly overrated. For those of us who get fish shipped to us, acclimation can mean losing fish not saving them. We do what is called plop-and-drop. Open the bag, pour the water and fish into a big net over a bucket and then add the fish to the tank.
Most fish can live in a range of parameters. You never seen it stated anywhere that they must be in exactly 78 F water or only in pH 7.2 for example. Some fish actually thrive on change, think of seasonal spawners where the conditions between the two seasons are very different and the changeover happens quickly.
Further, I have looked for papers on acclimation of fish. These are not so easy to find. Most studies which look into what is bad for fish also have to kill them. The statistic used for a lot of the is how long something takes to kill half the fish in the trial. The best research I have found deals with temperature. The goal is to know at what high and low temps the fish are going to die and then how they behave as they approach these temperatures.
However, these sort of studies do tell us about acclimation because in most case the fish to be used in the experiment are acclimated in the lab before the experiment begins. And these acclimation times vary from a week to a month. That is a big clue about how long acclimation may take. I did find one temperature study which also asked the question, what if we observe fish behaving such that we know they are going to die shortly because the water it too hot or too cold, can they be saved? The answer was yes, and the way was to move them back into their normal temperature range ASAP. No acclimation!!!!
I did find one study dealing with acclimating zebra danios (not using a formal citation, sorry).
Gill membrane remodeling with soft-water acclimation in zebrafish (Danio rerio)
Abstract
Little is known regarding the ionoregulatory abilities of zebrafish exposed to soft water despite the popularity of this model organism for physiology and aquatic toxicology. We examined genomic and nongenomic changes to gills of zebrafish as they were progressively acclimated from moderately hard freshwater to typical soft water over 7 days and held in soft water for another 7 days..........
From https://journals.physiology.org/doi...jkey=0e0761615a8a2d19ae1330103710509d7e03eadb
It took days for the physiological changes which accompany true acclimation to manifest.
As for your stocking, yes you can do it over a few days. However, try to add the bulk during the first 24-48 hours. Stores can have healthy tanks one day and not the next. They do not normally acclimate fish and want to sell them quickly. Also, the more fish you have at the outset, the fewer potential cycling related issues you can have with later additions which take much longer to acquire.
Think of it like this greatly simplified example. A tank when fully cycled can hold 10 fish. But one only adds 5 fish and then waits a month. The bacterial colony dies back to accomodate those 5 fish. Now if one added the other 5 fish, the bio load is doubled and there will be ammonia and nitrite spikes. So one would need to add new fish slowly. One new fish would increase the bioload 20% and two would be 40% etc. One the other hand, if one started with 5 fish they could add two then three for example with fewer worries. And if one started with 7, they might even get away with the next 3 all at once.
Why many do not acclimate fish shipped in. It has to do with chemistry.
So, the fish have been adequately purged so they will not poop much if at all in transit. They have been properly bagged in clean water. And away they go. What is now happening in the bags?
Every time a fish exhales it excretes both ammonia and CO2. The CO2 will create some acid which will start to drop the pH in the bag water. This is a good thing because as the ammonia level is building up, the lower the pH in the water, the more of the ammonia that will be in the less toxic form of ammonium, NH4.
About a day later (or more) the fish arrive. There is a decent amount of ammonia and CO2 now in the water but the ammonia is NH4 and not yet a worry. But, when the bag is opened what will happen. Fresh air goes in and the excess CO2 in the water to comes out. This lets the pH go back up. And that means some of the NH4 will turn into the very toxic NH3 form which is ammonia and which harms fish in concentrations as love as .05 ppm. The longer the fish is in the bag, the more toxic the water becomes. And this happens pretty fast.
Most fish, if healthy, can withstand changing conditions up to a point. I normally want to know in what parameters fish I am getting were being kept. I also keep mostly fish which will thrive in my well water and I Q all new fish. A month for tank raised and three months for wild caught.
, so if I am wrong and nitrite is not clearly under 1, then wait until tomorrow morning and it should be by then.
