The Science Behind Acclimitisation

[Miss Wiggle]

ok so there's a lot of different methods of acclimitising fish, but most go on the basic principle that you float the bag to adjust the temp and gradually mix water from your tank and the bag then release the fish.

i've just ordered and received some corydoras hastatus from trimar, drip acclimitised them and over the 3/4 days since i got them i've lost half of them. can't fault trimar they were excellently packaged and got to me quickly, i know these fish while fairly hardy once settled can be tricky to acclimitise so i expected possibly 1 or 2 deaths but not to loose half of them.

was just discussing this on the cory forum and was told of a different method of acclimitising particularly when fish have been shipped here is the quote from this topic http/www.fishforums.net/index.php?showtopic=200041

was just wondering what any of you with a more robust understanding of science than I have think of it.

Here is a copy and paste of the article on acclimating:

Here is the portion of the order acknowledgment from CorysRUs regarding acclimating new fish:

"For those who have ordered livestock please read the following:

We do not feed any of our fish we are shipping the day before or day of shipping. This helps to ensure that they will not have an issue and pollute their shipping water. We also use conditioned water and we add Ship Right which is a complete water conditioner and fish calmer for long distance shipping of tropical fish. Also guards against fish diseases, while the calming additive reduces stress and fighting among fish. Fish arrive in the highest quality and best overall health.

All of our fish are fed live blackworms daily in the AM and then one of the following in the PM: frozen tubifex, frozen dapnhia, frozen spirulina enhanced brine shrimp, freeze dried shrimp powder, freeze dried salmon roe, freeze dried earthworms, high quality flake food pre-moistened in water, Hikari Tropical Sinking Wafers which are specifically developed for Corydoras catfish and other bottom feeders after extensive research into their nutritional requirements and eating habits, and most often we use Boyd's Vita Diet 1.0mm crumble which is the only fish food fortified with Vita-chem. For pygmy corydoras we also feed Hikari Micro Wafers. We go to great lengths being diverse in our feedings not only to benefit the fish but also their future owners.

We have a lot of people write us and tell us their new arrivals will not eat. Don't fret, they can survive up to 7 days without eating. Remember, they are having to get accustomed to new surroundings, new water chemistry, new feeding schedule and all that stresses them out. Eventually they will usually come around and decide they have to eat what they are fed or go hungry.

When you receive the box open it as soon as possible in a dim lit room. The fish have been in a enclosed dark area for all the time they have been traveling sudden light causes unneeded stress. Allow the bags to float for 10 to 20 minutes to allow temperatures to slowly equalize (longer if necessary). Open the fish bags only when you are ready to immediately put them into your aquarium. DO NOT put any water from your aquariums into the bags or vice-versa! Avoid netting as much as possible. Gently pour off most of the water from the bag through a net. Then release the fish from the bag directly into the aquarium. Another good method uses a plastic container with sieve holes in the bottom (a smooth plastic spaghetti strainer with small holes works great). Gently scoop or release the fish into the container, drain the water and place the fish immediately into the aquarium. Large specimens can often be simply hand placed into the aquarium. If these methods are not applicable, place a large net over the top of a clean container with enough water to cover approximately a third of the bottom of the net. Open the bag and carefully pour some of the fish into the net and immediately place them directly into the aquarium. Try to avoid a net full of fish as they will ball up in the net, and the ones underneath can be damaged from compression and friction. Remember that water from the bag may react with the water from the aquarium, and could be very harmful. Never mix bag and aquarium water! That evening feed a very small meal and over the next few days slowly up the feed.
Sometimes during shipping, fish lie at the bottom of the bag and appear dead. "Playing opossum" is a common animal stress behavior. Carbon dioxide also acts to tranquilize the fish. Even if the fish look like they are mostly dead, put them into an aquarium as outlined above. Leave the aquarium lights off to further reduce stress, and leave them alone. You will be amazed how clean water and stress reduction help !

Like other animals, fish produce carbon dioxide as they breathe. When carbon dioxide is dissolved in water, an acid is formed, lowering the pH of the water just like in a carbonated beverage. Fish also produce ammonia, which can be very damaging. Ammonia is present in water as NH3 or as NH4+, or as a combination of these forms. The toxic form of ammonia is NH3. The proportion of NH3 versus NH4+ is dependent on pH. The lower the pH, the lower the amount of NH3, and the greater the proportion of the less damaging NH4+. In the wild, freshwater fish naturally experience wide changes in pH.

One of the reasons fish are able to be shipped long distances in closed bags is because the pH in the shipping water drops, making the ammonia non-toxic. The carbon dioxide acts as a tranquilizer. The moment the bag is opened, and exposed to the outside air, carbon dioxide escapes, the pH of the water immediately begins to rise, and ammonia becomes deadly. Fish tissue damage will then occur very quickly. NEVER add water from a shipping bag into your aquarium, as you do not want all that harmful ammonia in your aquarium. NEVER add water from your aquarium into the shipping bag. Acclimate the temperature by floating the bag in the aquarium water, and then immediately open the bag and release the fish into the aquarium, minimizing the introduction of the bag water.

It is very normal for new arrivals not to have any color for up to 48 hours and to be scared or lethargic. Within 48-72 hours they should be colored up, however, they can still be a bit nervous of their new surroundings."

The science of it is highlighed. This is the bit that CorysRUs emails with the reciept (or whatever I got it with) for a purchase. It was an eyeopener.

I didn't mean to say yours were ammonia burned. I didn't know if you had picked them up.

ICEEGRL used this to acclimate the fish I shipped her and apparently they spawned and laid viable eggs the day she got them. She had fry 4 days later. (First spawn too. I'm a proud gramma.)

My pandas are already spawning from Bryan. The fish had color immediately and showed none of the usual stress.

personally i'm not convinced of the idea that fish don't suffer from pH shock, Ian's tank runs at a pH of 5.7 due to the substrate, our tap water is at 7.2 first time we did a water change after adding the substrate we lost a few fish and others were floating around the tank aimlessly, clearly in shock. when we do water changes now we run water in slowly, on the same principal as a drip acclimitisation, the pH gradually adjusts and we've not lost fish since. although i appreciate this is a very big pH change, a smaller change of a few points would cause less stress I'm sure.

i do agree that ammonia is more toxic when the pH is higher, i'm fairly certain this has been proven.

do you think the bit about the ph rising sharply when you open the bag is true? do you think fish do suffer from pH shock and (obviously there will be differences for each species) is there a certain amount of pH change that fish can tolerate?

 

[rdd1952]

I'm definitely not a science expert but I do agree that sudden major changes in pH are not good. I too use the method of floating and adding water but I have never ordered fish online so the ones I have added had only been in the bag for 30 minutes to an hour when I got them home. I can see where there would be a higher amount of ammonia in the bag once it arrives but would't think it would be an issue as far as addiing it to your tank. After all, it's less than a pint of water in most cases and your adding it to 30, 60, 90+ gallons of water. Even if the ammonia reading in that bag was up to 10 ppm, it would probably not even result in a detectable amount once added to your tank.

 

[Miss Wiggle]

it's not so much the idea of adding water to your tank that bothers me, it's pretty simple maths to see that it shouldn't be too much for a well filtered mature tank to take care of in most instances.

but with a drip acclimitisation the fish are in the bag which has been opened for another hr or so, the water is being dilluted in this time but probably only by 50% or something like that. if the pH and therefore the ammonia does go sky high after opening then it makes sense not to leave them in there too long. just not sure if that's right or not.

 

[rdd1952]

I agree. The other thing I don't like about drip acclimation is that it takes so long that the water temperature that the fish are in is too low. I tried it once with the container sitting on the floor. Even with the thermostat in my house set at 76 the air temperature on the floor is only about 73 (hot air rises) so the temperature the fish are in is too cool in my opinion.

I've never had any problems with acclimation the way I do it even when I got my angels which were in very low pH water. The bag water (I always test it before starting to acclimate new fish) was at 6.0 or as low as my test kit went while the water of the q-tank was at 7.2. I spent 3 hours adding water gradually (about 8 oz at a time) to the bag every 12 minutes and it took over an hour before I could even see a change in the bag pH which made me believe the bag pH was probably somewhere in the 5s when I started. That was over 2 years ago and those 4 angels that were about the size of a quarter then are now about 3" long and doing just fine.

 

[Miss Wiggle]

I agree. The other thing I don't like about drip acclimation is that it takes so long that the water temperature that the fish are in is too low. I tried it once with the container sitting on the floor. Even with the thermostat in my house set at 76 the air temperature on the floor is only about 73 (hot air rises) so the temperature the fish are in is too cool in my opinion.

I've never had any problems with acclimation the way I do it even when I got my angels which were in very low pH water. The bag water (I always test it before starting to acclimate new fish) was at 6.0 or as low as my test kit went while the water of the q-tank was at 7.2. I spent 3 hours adding water gradually (about 8 oz at a time) to the bag every 12 minutes and it took over an hour before I could even see a change in the bag pH which made me believe the bag pH was probably somewhere in the 5s when I started. That was over 2 years ago and those 4 angels that were about the size of a quarter then are now about 3" long and doing just fine.

with drip acclimitising i float the bag in the tank which keeps the temp constant and at an acceptable level. sit a jug of tank water above the tank and run an airline with a knot in from the jug to the bag.

this is the first time i've had any problems acclimitising any fish, admittedly these are delicate fish to acclimitise, but i'm now wondering if there is something wrong with the method i use

 

[CFC]

I've always used the airline drip method to acclimatise fish from different water chemistries to London tapwater and have never lost a fish during the process. The water that Trimar ship in is extreemly soft so it takes longer to equalise than some other places but still no more than 6 or 7 hours.

 

[Miss Wiggle]

I've always used the airline drip method to acclimatise fish from different water chemistries to London tapwater and have never lost a fish during the process. The water that Trimar ship in is extreemly soft so it takes longer to equalise than some other places but still no more than 6 or 7 hours.

now your bringing hard/soft water into the equation too! i get a bit lost with gH, kH etc

i drip acclimitised for a bit longer than an hr, the bags were full to bursting by then and the cories seemed happy and active so i released them, would you advise doing a drip acclimitisation for significantly longer than i usually do then?

 

[rdd1952]

The way I was told to do the drip method was to pour the bag contents (fish and water) in a small container (I used a 2.5 qt container) and place it in a 5 gallon bucket. Then start the drip into the small container. Once the small container fills, it will start to flow over into the bucket. This would still be diluting and mixing the tank and bag water. It seemed to work well but as I said, the only problem I experienced with this is that the water seemed too cold in the bucket since I had to put it on the floor.

 

[CFC]

now your bringing hard/soft water into the equation too! i get a bit lost with gH, kH etc

i drip acclimitised for a bit longer than an hr, the bags were full to bursting by then and the cories seemed happy and active so i released them, would you advise doing a drip acclimitisation for significantly longer than i usually do then?

I run the drip until the water in the bag matches the parameters of the water in my tank, before starting the drip i test samples of the water in the bag and the tank for pH, KH GH and nitrates (and SG too if its a salty tank) and then re test the bag water every hour until i am satisfied that there is a good match. In most cases this only takes an hour or two at most but i have drip acclimatised animals from freshwater to high end brackish water which has taken around 10 hours to get a match. I usually do away with the bag all together and providing there is enough water to do so pour the fish and bagwater straight into the poly box.

 

[Miss Wiggle]

maybe i've just been lucky, maybe it's cos i don't usually get delicate fish, but i've never gone to that much bother with acclimitising and this is the first time i've lost fish from it.

 

[Miss Wiggle]

what i'm wondering is are the effects of acclimitising as described in the first post a theoretical or real risk. would a few fish, packed sensibly and transported to their final destinations say within 24hrs really produce enough Co2 to drive the ph down to a point where the ammonia is not harmfull to the fish? I don't think ammonia will ever be non toxic as described in the first post but at a lower pH it is significantly less harmfull than at a higher one. Obviously there's a lot of variables such as the size of fish, when they were last fed, how much air/water they were packaged in etc etc.

only way to tell i guess is to test the Ph of the water when it's packaged and when it gets to you, can't test the water without opening the bag though so you'd have to have some sort of permanenet test packaged with them. hmm

 

[andywg]

First up, one must consider what they are saying is happeneing. It is being claimed that there is so much CO2 being produced by the fish in transit that they are forcing a higher take up of CO2 in the water, thus affecting the pH.

First off, what is the Alkalinity, or Carbon hardness of the water when it starts being shipped? A higher KH will buffer against the water turning acidic, but very soft acidic water to start with may have some problems.

Secondly, consdier how the CO2 is going to stay in the water at a higher saturation. Anyone who has tried planting a tank knows you have to decrease the surface agitation to prevent the CO2 gassing out of the water. A similar effect is likely to happen through the shipping.

A pressurised, or sealed container may hold some of the CO2 in andcause increased saturation of CO2 in the water, thus effecting the pH. When the container is opened (think of a coke bottle once shaken) when you open it the saturated gas will leave the solution.

Any SCUBA diver will know this effect of hypersaturation and gasses leaving suspension as the cause of DCI, or the bends (though I have grossly oversimplified the mechanics here).

My guess would be that in order for the shipping water to increase the pH to a level where the ammonia/ammonium balance is affected that wuickly, then it will also be a pH shock as well. Furthermore, consider Bignose's table showing the relationship between temperature, pH and ammonia/ammonium balance (a thread surely worthy of pinning).

Next time someone gets some fish shipped, get a pH test done the moment the bag is opened and measure it to this table and see how different the level of pH is from the tank water. I am betting you will not be seeing a pH down in the 5 region where real difference in the %age of ammonia/ammonium starts to get a long way from those above it.

If the amount of CO2 expelled by the fish has caused the pH to drop down into those levels, and opening the bag causes a swift rise of the pH back again, I would expect to see some CO2 bubbles forming in the water (remember the coke bottle) as they leave solution due to the lower partial pressure of CO2 in the air now the bag is opened.


In conclusion, I believe that the first post has some hypothetical merits, but i just find it hard to believe we will see huge enough pH swings downwards (and let's be honest, 2.0 is a huge swing) in practice to really make that an issue.

Also, if you do get those low pH readings, do you really want to throw the the fish from pH 5 to pH 7? that is a huge swing and one that a great many fish will not appreciate after a stressful journey.

 

[Miss Wiggle]

In conclusion, I believe that the first post has some hypothetical merits, but i just find it hard to believe we will see huge enough pH swings downwards (and let's be honest, 2.0 is a huge swing) in practice to really make that an issue.

pretty much what i thought

thanks andy

didn't think about the surface agitation side of it, after getting splashed around on a journey (which will happen however well packaged they are or how careful the driver is) i'd expect the air to have a higher Co2 concentration in it that the water.

 

[Dave Spencer]

didn't think about the surface agitation side of it, after getting splashed around on a journey (which will happen however well packaged they are or how careful the driver is) i'd expect the air to have a higher Co2 concentration in it that the water.

In the confined space of the bag, I would have thought that the water and air CO2 levels would equalise, just as they do in a CO2 drop checker.

Plus, once the CO2 content of the water gets much above 30ppm, the CO2 concentration is higher than in the fish respiratory system, meaning that the CO2 blocks respiration, so levels builds up to a point where the fish become lethargic due to their inhibited ability to take up O2 and ultimately die.

Dave.

 

[Miss Wiggle]

yeah you think? inside a drop checked the water's not turbulent though is it? would that make any difference?


is there some sort of ratio or calculation for how much Co2 you have in the water and what the ph is, like if you add 10ppm of Co2 to the water the pH will drop by 0.1 or something like that?

then we can work out what level of Co2 would need to be in the water to make the pH drop by the 1/2 points it would take for the level of ammonia to be significantly less toxic to the fish