Acclimating and introducing new fish to the aquarium.

1) The basics.

Fish acclimation, it should first be understood, has no hard and fast rules. Some petstores will give you a fish quite literally with instructions on the bag, but whether to follow those instructions or not depends on a number of factors including, the species of the fish, the amount of fish, the amount of water in the bag, the water /air ratio, the water quality at the shop, the water quality in the home, and the journey time and atmospheric temperatures during the journey. Also the type of packaging, be it a porous breathable membrane, or just a regular plastic bag, or a foam crate will make a difference, as will air or oxygen used in packing, or whether salt was used in transit affect matters too.

Its pretty much common knowledge that you must, one way or another, prevent environmental shock happening to your fish as much as possible. But how do you do that? What are your primary concerns?

So do you take 2 minutes to float a bag in the tank? Ten minutes? Half an hour? Is ph most important? Is hardness? Is temperature? Well actually its oxygen.

A) Fish must breathe.
THIS IS THE BIG ONE. Aside possibly from impact shock in transit, which, lets face it you can do little about if the fish was shipped to you, the first thing to worry about is if the fish still has enough saturated oxygen remaining to be able to breathe in the bag long enough to get used to ph, temps and whatever else for a gentle acclimation. Quite simply, if it doesnt, you have to release it into the tank, or drop an airstone in the bag. Whatever happens after that is lap of the gods stuff, the fish will either make it , or it wont. If the fish is struggling to breathe in the bag then all other considerations are strictly secondary. If the fish was bagged properly, ie, 50/50 air and water in the bag, and at least 20-30 times the volume of the fish of water, it has on average up to 6 hours in the bag before breathing becomes difficult. If the fish is too big for the bag or there are too many fish in a single bag , you may have only an hour or less. Fish packed with extra o2 injected into the bag when packed or breathable membrane bags may give a fish as long as a couple of days. Its important to know how your fish was bagged, and it helps if you bought the fish yourself to have asked your LFS what their water perameters are. Any traceable ammonia or nitrite in the bag will shorten the time immensely, and on longer journeys a presence of high nitrate will possibly indicate high bacterial and detritus levels, and this too may compete with the fish for oxygen. Over 80 ppm will be real trouble. It helps to know these factors because most fish find being caught and bagged , and shaken about during travel intensely stressful, and they will be respiring rapidly in panic, and it helps to have a clue about whats really going on chemistry wise in the bag, rather than just taking a guess that the fish is suffocating when its actually panicking, and may yet calm down. Extremely panicked fish are a problem too, and a fish that wont calm down will have to be released early, as they will be hyperventilating and using oxygen at a massively increased rate, possibly even quartering the amount of time you have left to get them out of the bag.

Species is important here. Fish with labyrinth organs or primitive lungs, like bettas and gouramis, various polypterus and lungfish would be extremely unlikely to suffocate in a bag , and you can usually take your time acclimating them. Sedentary fish like doradids and banjo cats also tend to use very little oxygen. Others like hatchetfish, butterfly fish, rainbowfish, river cichlids, hillstream loaches , hara hara's, jewel cichlids, etc, basically any fish that likes low temperatures, fast flow rivers, or surface dwellers will have to be observed most carefully, and any sign of respiritory difficulty taken extremely seriously. High temperatures in transit are to be religiously avoided, they will affect the amount of saturated oxygen water can hold and thusly be available for fish breathing. Much over 85 f and youre in trouble, though a lot of tropical fish can take surprisingly cool temperatures for short periods.

B) Temperature. This is not an abstract killer, it kills because of one major reason and that is swim bladder failure. Temperature affects gaseous activity,molecular oscillation, and the expansion and contraction in the tissues of fish, and sudden hikes and lows of temperature over a few seconds can cause swim bladders to either expand with rapidity, massively causing them to burst, or to contract to the point they may never be reinflated, and in either case if the swimbladder adheres to the surrounding organs then that, as they say, is pretty much it. Air from a burst bladder getting stuck into other organs can be equally fatal, as can gas bubbles expanding to impede circulatory function in a fish. Most fish can take 1-2 degree fareinheit difference with no problem, but if the difference between the bag and the tankwater is more than that the fish absolutely will need to be floated unless of an unusually tolerant species. Fish of most concern will be species like angels, scats , mono's, and discus, who have complex bladders and a total dependancy on them for balance, rams are very temperature sensitive,as are most apistigramma, juvenile fish of almost all species, and fancy goldfish, and the numerous "balloon" variants of ram, molly and others. Average floating times need be no longer than 10-15 minutes, unless the bag is very large indeed. Bagging and floating is a necessity, unless the fish are already home, and the transfer is simply from one tank to another with identical conditions in which case the fish can simply be netted and dropped in. The floating of a new fish is always necessary.

C) Stress.
In this case meaning the mental inability of a fish to cope with fright, and control its flight responses.Ultimately if this is not given proper consideration the mental state can quickly become a physical state, and the fish may go into physical shock as if literally critically injured. This state includes the retraction of circulation to anything but the most vital of organs, meaning the fish effectively paralyses itself, and while some fish can automate themselves back out of shock, others become locked into the paralysis, and unlike with mammals there are no steroidal stimulants available for fish, so a fish locked into shock will die, usually from respiritory failure. Long term stress leads to illness, but high levels of short term stress encountered in transit can kill a fish outright.

It is therefore absolutely imperative that shock be avoided in the first place. Distress is almost unavoidable whenever a fish has to be moved to different accomodations, and in transit it is imperative that the fish remain dark and covered. DO NOT let children play with the fish bagged in transit, and its better not to check on it during the journey (even if it is suffering, what are you gonna do? Whip up a cycled and planted 40 gallon on the motorway?). Keep the fish dark, quiet, and as free from tipping , vibration, and changing temperatures as possible. Get the fish to destination as quickly as possible. This is not the time to take in the local scenery or stop off for a pub lunch. Short journey times seriously increase the chances of survival and lessen the chances of shock. Keep this up right until the point its literally time to float the bag in the water of the destination aquarium. When it gets there, its better to keep lighting around the tank subdued, it helps if the fish cant see beyond the internal reflection of the glass to see those big scary human things, and for nocturnal species, completely off is better. Limiting the fishs visual stimuli is extremely important during acclimation. The less it can see, the less it metally has to be frightened of, or deal with. The lateral line on the fish will respond to bangs, knocks and violent movements, keep things slow and graceful, think before you move around the tank, and especially when holding the bagged fish. Avoiding overstimulation of any type is key.

D) PH and water perameters. This is too often worried about. On the proviso that the water values are correct for the species, and the tank is cycled and clean the chances of water quality shock are absolutely minimal.The instructions on the bag as regards dropping tankwater into the bag over a period of minutes is needlessly paranoid for most species, and particularly if the temps are near as need be, and the fish may be running out of oxygen, simply forget it. Unless youve bought some seriously inbred discus or the most fragile of specialist cichlids there is no need whatever to do this, and in fact you may actually be changing temperatures, which are a much bigger risk , too quickly to be helpful to the fish. (Do you seriously think you can get fish used to water perams other than temperature in a few minutes? It takes DAYS, and in some cases ph acclimation may take weeks or months!)If you were trying to acclimate a fish to a water quality outside of normally recognised ranges , this would be a problem, and not one dripping water into a bag would necessarily solve anyway. Basically dripping small amounts of water into a bag to get it used to ph and nitrate levels and the composition of the water is a ridiculous myth. This is not a process you can perform in minutes. Temperature and oxygen are the major concerns.Water composition is something the fish has to get used to over the first weeks of aquisition. Personally I have never bothered to add tankwater to the bag in 25 years of fishkeeping, and thats over 600 successful personal acclimations in the last year alone. It wasnt necessary at home, or at the fish store in which I worked. Most fish stores run blanket conditions across the board whether they are suitable for the species they keep or not, and reverting them to the preferred water ranges recommended for fish in the home immediately almost never in my opinion , does any damage whatsover. If however, you are placing a fish into a water perameter situation unsuitable for the species tolerance ranges, then obviously you can expect to lose some fish, under any cirmstance or method of acclimation. The initial acclimation time gives you no period long enough to deal with this factor.

E) "How valuable are stress aids and chemical additives?" In truth, not very. The stress that most fish suffer on acclimation is a mental state, not a result of water conditions, but because of a series of shocks, and fear. Short of calming it with a mild version of an anaethetic ( which would be wildly impractical and actually very dangerous ) there is no way to do this.To be honest you can throw all the aloe vera and salts at a fish in the world, and it makes precisely no difference. The physical shock a fish can suffer as a result of mental distress can only be stopped by ending the distressing stimulus and allowing the fish to return to a routine life as expediently as possible. Stimulus reduction is the key, hence keeping a low profile, and keeping things calm and dark. Feeding tricks are diversionary tactics, and likely the only ones to work, theres not really anything else that can be done , except with shoaling species for whom the company of their own species can be intensely soothing, but again, you flout quarantine at your own risk. For shoaling species its probably better to procure a few specimens at once rather than have them go through quarantine alone.

2) The next stage.

Ok we are assuming that so far, the fish are at temperature, havent suffocated or been frightened to death and your ready for release into a new tank or preferably quarantine. You add fish into an established community from a petstore without quarantine at entirely your own and your fishes risk, it is NOT advised. Likewise you do not put the petshop water from the bag into your tank, even if it is a quarantine aquarium. That tankwater could contain literally dozens of diseases from fish all over the world from a shop system and your fish might not be infected, protected thus far by its immune system, but your fish because of stress is likely to suffer a short period of immunosupression. Therefore you should divorce your fish from its old bagwater as expediently as possible, and leave as little of it entering a new clean tank as possible. Basically net the fish, drain it for a couple of seconds and flip it into the tank free of the water that previously surrounded it. Practised keepers may elect to flip the fish out manually, but generally its not advised to touch a fish that may have been bruised in transit.Skin slime layers are easily damaged by contact with dry or grippy human skin, and with immune system on the way out in the coming days, the skin slime layer is all a fish has to protect it. For this reason its also advisable to have pre-sterilised nets with a little boiling water and allow them to cool before using them to catch the fish.

Hopefully there will be some cover in the new tank and the fish will likely head straight for it and stay there. LEAVE THE FISH ALONE. Do not stress it with your presence, and do not start rearranging plants and decor. Shut up the tank and leave it alone for at least a few hours and preferably the whole day. I know its exciting to have a new fish in the house, especially if its your first one, but keep kids, family pets and other similar miscreants the hell away from the tank. Keep a casual eye out for how the fish is doing , but keep hands out and faces away from the glass. DO NOT tap the glass to see if the fish is ok unless you seriously want it dead.

A common question at this point is "Can I feed the fish?". Most classic literature will tell you not to, and with any fish likely to have swim bladder complications as mentioned above its better not to feed them for at least a day. This is particularly true for fish that have encountered long transit times, as they really do need time to get their metabolism in order before you risk putting a strain on the heart, stomach, and respiration by feeding them, maldigestion can complicate matters and could lead to some dead fish, but for fish that have only had a half hour or less transit time, and of a not an especially fragile swimbladder proclivity, you can actually feed them with very little risk to their health. In actual fact feeding a fish, particularly with livefoods can sometimes ease a lot of stress. Often the less intelligent the fish, the more compulsive the feeding response, and occassionally a quick, small feed can take their mind off their own panic. Some of the quickest acclimations, in the authors opinion, do actually happen when the fish has fed.

Its not a good idea with other hungry shoaling species present though, as a new fish with a batch of food dropped next to it might find a shoal not unlike a football crowd mobbing over it to get to the food,and panic may ensue, but if your tank inhabitants are calm, or this is a single fish situation, it doesnt do any harm to give it a go, and it actually means you can confidantly leave the fish alone to feed in peace for the day, and not rush to interfere with it the following day. If the fish doesnt eat though, obviosly you dont want to have put a great deal in because of the risk to water quality. Make the first feed very light. Feeding responses are a great way to combat stress, on the proviso that the fish is not so physically tired that it could cause a strain on its metabolism. If in any way unsure as to the condition of the fish, feed on the day following aquisition.

3 Finding normality.
While its perfectly true that most fish need no strictly adhered to time for feeding in the long run besides a rough adherence to their average diurnal or nocturnal activity, ( the author himself pretty much feeds fish innately, ad-libitum and according to nutritional need,) in the beginning a routine can be very important to ease the fishy mind. Keep feeds at regular hours, and make sure the photoperiod (lights on time!) is regular, around 12 hours a day ( reflective of equatorial times for most tropical fish, and this is most important for wild collected fish ), and if at all possible, graduate the change from dark to light. In combatting stress, whether the fish just rest or actually sleep , it is very important they are not disturbed. As standard practice, consider the risk of physical shock to be very apparent for at least a couple of weeks and even if the fish dont die directly of shock, a stressed fish will be immunosupressed and dozens of times more likely to become victim to disease.

Any tank maintenance is best avoided for at least a week, although obviously if you omitted something that might have dangerous conseequences, or have to provide more cover you may have to break this rule a little. For the first time fishkeeper this will of course be a time of learning, and while you should aim to do as little either in or around the tank as possible, keep an eye on the fishs behaviour and remember the modifications you may wish to make as some point later on. The longer you can put them off, the happier the fish will be. Just feed the fish, and observe it, keeping a watchful eye for disease , disease treatments during this vulnerable time must be administered immediately, with a low immune system the fish will have no defense and with that in mind a new fishkeepr fight consider an anti-fungus and finrot medication, and an anti-ich, or whitespot cure a good thing to have as part od the ol fishkeeping armoury. You dont want to find out that the fish you bought on the weekend is diseased and that you cant get meds until later in the week, the fish might not make it that far.

That's pretty much it! The rest is all the regular daily business of fishkeeping.

Happy fishkeeping!