How Do You Introduce Fish to your Tank?

[MuddyWaters]

When bringing home new fish, I have always added the bag to the tank for awhile to get the temp the same, then put the fish and the store water into a large container (smaller than bucket) and slowly add water from my aquarium over time (usually 30 - 40 minutes with a small pour of aquarium water every 10 minutes). Then I pour the water through a net and put the fish into the tank.

I did go through a phase where I got lazy and dumped everything (water and fish) into the tank. I had bad results with this.

I have just finished reading this article by David Bogert where he discusses the "Cut, Pour, Plop" method of adding fish to the tank. Very interesting! It appears that for fish purchased locally and brought home within an hour or two, the acclimation method is a waste of time at best. For fish that are purchased and shipped, the acclimation method can be deadly. Very interesting reading.

How do you introduce fish to your aquarium?

 

[Magnum Man]

I put my bags in a dishpan, then add about a cup of aquarium water to the bag 3-4 times, about 5 minutes apart, pour them through a net, over the dish pan ( dedicated for Fish use ) then add them to the tank... all my fish come from mail order... & depending on the distance shipped, & the amount of fish in the bag, I like to open them to the air right away, & get some air into the bag, & use the added tank water to bring the temperature close...

 

[CaptainBarnicles]

It can take weeks for fish to get used to their new water so adding tank water to the bag little by little does nothing but prolong the process....

I float the bag with the lights off to get the temperature the same, then I cut the bag and pour it into a net over a bucket and put the fish into the tank. Like ripping off a bandaid, it's kinder in my opinion

 

[Back in the fold]

I put my bags in a dishpan, then add about a cup of aquarium water to the bag 3-4 times, about 5 minutes apart, pour them through a net, over the dish pan ( dedicated for Fish use ) then add them to the tank... all my fish come from mail order... & depending on the distance shipped, & the amount of fish in the bag, I like to open them to the air right away, & get some air into the bag, & use the added tank water to bring the temperature close...

That’s exactly what I do now . Before I would float the bag for a half hour and then pour them in water and all . A wonder I never had any disasters .

 

[Essjay]

I do the same as CaptianBarnicles, float to equalise the temperature then fish straight in the tank. But no store water.


The reason the adding water over time can be deadly to fish which have been shipped is ammonia. While they've been in transit they've been excreting ammonia and breathing. They breathe out CO2 like we do; this builds up in the water and lowers the pH. Ammonia is less toxic at low pH, so the fish are safe. Then they are delivered, the fish keeper opens the bag and that dissolved CO2 gasses off - and the pH rises making the ammonia more toxic. The fish now sit in this toxic ammonia for however long the fish keeper spends adding water to the bag.

 

[Magnum Man]

I add the 1st cup of tank water to the bag, as soon as I open it, & most fish bags don't hold much more than a couple cups, unless you are buying quite large fish, so at minimum its a 33% water change / dilution, as soon as the bag is opened... I've never lost a fish, since I got my tank water straightened doing this, & I've been buying quite a few fish, to fill up the old tanks I've been restarting lately

 

[emeraldking]

How Do You Introduce Fish to your Tank?​

I'll keep them in a separate tank first for a number of days before they'll enter their final tank.

 

[Ichthys]

It only takes literally a minute or two for the temperatures to equalise, so don’t leave them too long.

You need to test the hardness and pH of both the bag and the tank. If they’re very similar, you can chuck the fish straight in. If they’re wildly different then a gradual mix will usually prevent osmotic shock.

Always add diurnal fish with lights on, so the fish can assess whether it’s going to be safe or not. Adding them in the dark is adding them into an unknown world when all the nocturnal predators are out and it can’t see them and doesn’t know where it can hide.

I like to add nocturnal fish with lights off, so it can assess the tank without having to immediately hide and wait for darkness to find out if it’s going to be safe or not.

 

[emeraldking]

To me it's not particular the temperature difference that is important, but more the other water parameters. For if I buy new fish, they could have been kept in water with different water parameters. And of course, if they carry some illness. That's why new fish will always be kept separate first for a while before entering their final tank.

 

[GaryE]

My fish go into tanks with no other fish. Qt is essential, even if I know the source. Everyone gets unpleasant surprises sometimes.

I equalize temps, and our the fish into a net in a bucket, to keep the transit water out of my tanks. This is especially important to do with pet shop fish, where the pathogen load in the water can be high.

I work fast. I want my fish out of that water. I tend to get wild caught fish by preference, and they are often in the water they were shipped in. I do my homework, and know what the needs of the fish are. I'm not going to be careless and buy a hardwater fish for a softwater tank, and I don't believe in the old myth all fish are fine in the same water. If I buy a fish, I know my water suits its biology.

I consider drip acclimation to be a prolonged ammonia bath.

I can only speak to my own experience, but I have not had any acclimation issues with new fish since I started doing this more than 30 years ago.

 

[emeraldking]

My fish go into tanks with no other fish. Qt is essential, even if I know the source. Everyone gets unpleasant surprises sometimes.

That's why I put new fish always separate first...

 

[Slaphppy7]

How Do You Introduce Fish to your Tank?​

"Fish, meet tank...tank, this is fish"

 

[Naughts]

I agree with the science in the article, Get the fish out of the bag water and into the quarantine tank. Acclimatisation could never happen (in the case of soft water fish in hard water or vice versa) so slowing changing the water is at best futile, and at worst deadly.

 

[TwoTankAmin]

Plop and Drop. Fish can not acclimate to anything in a matter of hours. If the fish is in water where the temp. is at the fatal point, i.e. if left there the fish will die, the solution is to get it into the propaer tamp. water ASAP. So there is really no need to acclimate for temp.

Most of my purchased fish arrive shpped to me, they come out of the bagsa as fast as possible. When they are my fish returning home unsold from a show, they go back into the tanks from which they came. When they are newly acquired fish they go directly into a Q tank.

Chung, K.S. Critical thermal maxima and acclimation rate of the tropical guppy Poecilla reticulata.
Hydrobiologia 462, 253–257 (2001). https://doi.org/10.1023/A:1013158904036

Abstract​

Tropical guppies, Poecilia reticulata, collected from the canal of La Laguna Los Patos were acclimated over a four-week period at local water temperatures of 24–33 °C to determine their critical thermal maxima (CTM) and death points (DP), as criteria of thermal tolerance. In addition, individual thermal tolerance times at a lethal temperature of 38.5 °C were measured over 12 days for upward acclimation from 24 to 30 °C and over 16 days for downward acclimation from 30 to 24 °C to determine acclimation rate just before and after changing the acclimation temperatures. The CTM ranged from 38.95 to 40.61 °C and the average DP varied from 41.22 to 42.86 °C. Positive relationships were apparent between thermal tolerance and acclimation temperatures, and thus heat tolerance criteria (CTM and DP) were significantly different among acclimation temperatures. Individual heat tolerance times increased most rapidly during the first 6 hours of upward acclimation after transfer from 24 to 30 °C, continued to increase another 5 days and fluctuated after initial acclimation was completed. The heat tolerance times of fish transferred from 30 to 24 °C declined steadily over times, reaching a minimum at 14–16 days after transfer.
https://journals.physiology.org/doi/full/10.1152/physiolgenomics.00195.2006
red color for text added by me

 

[seangee]

Plop and drop