Acclimatizing New Fish

[Morrgan]

I've always introduced new fish to the tank by first floating them on the surface to even the temperatures, and then slowly mixing in water from the tank with the water in the bag, in case of any chemical differences in the water.

Recently I've been reading up on new literature and came across two books that said that mixing new water with the old is unnecessary. The reasons for this would be that the LFS is most likely using the same tap water as you, and that fish take up to three days to adjust to new water so if there really were any differences, they would die regardless of this precaution. This means that the only thing necessary would be to even out temperatures, then let the fish out.

Is this true? I can see that this would be correct in the case of large differences, but what about small ones?

What about when you know there are large differences in pH and hardness, how do you go about adjusting fish to the new water parameters? I understand you start off by keeping the fish in a separate tank with the water they are used to (like a quarantine tank) and then slowly adjust them during several weeks, but exactly how do you do this? For example, how much new water can be added at once?

 

[guppymonkey]

I have never heard anything like the information you found. The best method for introducing new fish is the drip acclimatization. Like you described equalizing the temperature and slowing adding some of the tank water to the bag of fish. This lets the fish get used to the differences in water quality. It is true that most LFS have the same tap water as local buyers the water conditions always differ from tank to tank. Most pet stores don't use the best filtration on their tanks. This means that the ammonia, nitrite and nitrate levels are going to be completely different from what your tank at home would be. Also pH can differ from tank to tank.

 

[CFC]

Unless i have purchased the fish from a shop a long distance from my home (ie mail order) or i have a particually delicate fish then i just allow the temperature to even out and release the fish, so far after 6 years and a couple of hundred fish later i have never lost a fish introducing it to a new tank.

For mail order fish i quarentine the fish in the smallest tank possible for a few days adding as little of our water to the water in the bag as possible then change a little of the water every 12 hours until the pH values match to avoid the fish going into pH shock

 

[Gunnie]

I think slowly adding tank water to your fish bag doesn't hurt and will only help. I recently pretty much put my fish after 15 minutes into their new tank, and all 3 were dead within 24 hours. When I slowly added tank water to the bag every few minutes for about an hour, the fish seemed to do much better. I must also admit that the fish came from WalMart which could have been the reason for their deaths, but this last batch came from there also and they are still alive. I would say to slowly acclimate them to your tank water. It sure won't hurt anything.

 

[teknikz]

if im treating my water in the tank i catch my fish with a net so that there isnt an overdose in treatments......just incase the lfs has treated the fish and hasnt said.........otherwise i just float them for 15 mins then free them

 

[FishHeads]

I believe that those book syou have found are a bit whacky if you ask me. Mixing water leads to less shock when letting the new fish out. If you don't mix, the fish overstress.

 

[BettaBoyz]

ah, i'm completely against floating fish at all.

call me insane, but i think you are for doing it!

my dad has these ancient FAMA magazines and one issue has an article explaining that floating fish can lead to brain damage because the bags don't let gasses pass out, but let them in. they had an experiment where six Guppies from the same tank were kept in identical bags at identical temperatures, one floating the other in a dry spot, and within four hours the floaters died. within six days the dry ones were released back into the tank and went about their fishie business as if nothing ever happened.

i vouch for it. so far, each fish i introduced by floating ended up listless and of poor health; all my Tetras refused to move even an inch, these were floated. my Betta and Kuhliis were not floated, they are full of spunk. Pierce was floated for a little while in a newly-cleaned tank, he isn't as quick on the uptake as non-floated King. Mackenzie was floated, he never once touched any sort of food, and moved by flapping his ventrals around wildly. never used his pectorals or tail, he was floated for twenty minutes with the recommended water-introduction. there was never anything wrong with my water, it is always nice and clean and warm enough for the fishies. don't blame my water. i blame the gas. bad gas.

 

[Morrgan]

Thanks for the replies, all. Hmm, this seems like a tricky topic with many different opinions. Still, I've never lost any fish by introducing them the way I have so far, so I don't see any immediate need to change that.

guppymonkey, I too was wondering about ammonia, nitrites and nitrates. That's why I wasn't too keen to believe the advice given in the books.

Thanks for the info on mail order fish, CFC. It might come in useful one day.

FishHeads, the books I read seemed accurate and up to date in all other respects, that's why I thought I'd ask about it here instead of dismissing it immediately.

BettaBoyz, frankly I don't know what to make of your info. I've never heard of these gasses before and I can't see how the gasses would only pass through bags in one direction. Some kind of differences in concentrations? But wouldn't that mean that there'd be more of those gasses in the tank water than in the bag? What I do know is that large, sudden temperature differences can be detrimental to a fish's health, especially more delicate fish. All my fish have been floated and apart from being a bit stressed the first day (which could just be from being caught, transported and put into a new environment), they've been fine after that.

By the way, one more reason the authors gave (that I forgot to mention before) was that it would stress the fish more to have it float on the surface for a longer time, exposed with nowhere to hide, instead of letting it deal with possible slight differences in water. What do you make of that?

 

[guppymonkey]

That is an idea. Fish do seem scared and stressed when they are exposed with no where to go. But new fish are from pet stores that usually keep them in bare tanks so they have been under that sort of stress for days or weeks. I think the stress of completely different water conditions would do more harm than the stress of having no where to hide. Plus when the fish hide its a lot harder to find the bodies if they die. I found a dead neon that had somehow rammed its way under the bottom of a plastic plant. Strangeness......

 

[yhbae]

What about the ammonia build up in the bag? I imagine given the volume of water in the bag, the concentration of ammonia must build up pretty quickly.

I let the bag float but I start to add little water from the first second, hoping that any toxic chemicals in the bag would get diluted as well as contributing to help equialize the temperature with the tank. I do this over 20 mins or so and so far, I lost few fishes from one species only.

 

[rsz]

my lfs told me to float my bag for just 10 minutes in summer, because it was very hot and they said the best thing to do was to get him into the cooler water of my tank. when it's colder weather, i do half an hour, and put some tank water in. it seems to work for me.

oh, and lots of the replies state how lfs's dont have a substrate or have crummy filters ... mine must be very good because all the tanks have gravel, the same filter as me and plants for fish to hide behind