Do Fish Recognize Former Tankmates?

njhcnwk

New member
Just was wondering if fish recognize their former tankmates. more specifically, let's say I remove one of the fish to a hospital tank for a while. when I reintroduce that fish back to my dt, do the fish "know" each other still?
 
Just was wondering if fish recognize their former tankmates. more specifically, let's say I remove one of the fish to a hospital tank for a while. when I reintroduce that fish back to my dt, do the fish "know" each other still?
Only if they're owed money. Seriously, I doubt it very much.
 
Well, I know this is different because it involves a clownfish pair, but I had to remove one of my clownfish for a couple hours and they both looked panicked until I got them back together. Do not see why it should be different for different types of fish.
 
I doubt if they even recognize the same tank. Every morning when the lights come on, the fish come out and spend 30mins just exploring
 
Okay, so theoretically if one of the fish I removed was not getting along with another, then it's possible they will play nicer?
 
My experience was as follows: I added a fish from the LFS and it was beaten up by a tang. The tang finished in day like he usually does. This was before I knew the mirror trick. The new fish was weak and died. I quickly replaced it, less than a week later. (it was an inexpensive fish). The tang said, "Oh hey, you're back. Good to see you!" and left it alone. So the tang remembered!
 
Okay, so theoretically if one of the fish I removed was not getting along with another, then it's possible they will play nicer?

Why not tell us what's going on? Opinions will be based on the type of behavior and fish involved. A squabble over territory with a new fish is a whole different ball game than 2 incompatible fish---two female maroon clowns for example.
 
No, it's nothing extreme. I removed my sarghassum trigger to qt to be treated with copper. my japanese swallowtail likes to pick on him sometimes and he doesn't cruise around the tank like the other fish do. he seems to avoid the angelfish by hanging in the corner. i'm hoping for more activity out of him as he's a nice looking fish.
 
I would have to say no - reason being - I had a lawnmower blenny for many many years that passed away last fall or something. Anyway - I bought another one shortly after and it was like all of the other fish had never seen one before. They picked on the poor guy and chased it all over the place till it jumped.
 
No, it's nothing extreme. I removed my sarghassum trigger to qt to be treated with copper. my japanese swallowtail likes to pick on him sometimes and he doesn't cruise around the tank like the other fish do. he seems to avoid the angelfish by hanging in the corner. i'm hoping for more activity out of him as he's a nice looking fish.

If he's a new fish, he should learn his place in the pecking order and become bolder. Are you treating for ich or another parasite? If so, I'm afraid you'll have to QT all your fish, treat them, and let your DT go fishless to eradicate the stuff. If one fish has ich; the whole tank does.
 
sargassum triggers are naturally shy until they get adjusted to their tank which may take a while. How long has the angel been in the tank? When angels get settled and territorial they are big bullies to any new comers.

If possible I would QT the angel and place it back once the sargassum is swimming out in the open.
 
I would have to say no - reason being - I had a lawnmower blenny for many many years that passed away last fall or something. Anyway - I bought another one shortly after and it was like all of the other fish had never seen one before. They picked on the poor guy and chased it all over the place till it jumped.

Why would they recognize a replacement / new fish?

I notice that my tangs are very social and comfortable around family and close friends but when a stranger is near, they tend to be shy and hide. when the stranger leaves and we are still near, they are back to normal.
I would say that they recognize us but that doesn't say they recognize other fish.

My guess would be yes, if they weren't seperated for very long.
 
I say yes... I have re-introduced fish to tank with no problem that would otherwise have been torn apart.
 
I believe they recognize each other. I bought three tangs that had been in a tank together before mine. They were separated for a few days until my new tank was ready for them. The three of them were put back together along with a new aggressive purple tang. They all three instantly swam to each other and huddled up in a corner together. Finally the three of them together, put the purple tang in his place and took away his dominance. It was really interesting to watch.
 
I believe certain fish have memories capable of recognizing individuals. My experience with this has been in freshwater. At one time I had numerous tanks with large cichlids. In one tank a female managuensis paired up with a smaller male labiatus. Eventually, I located a large male managuensis that I paired her up with, in their own tank. Around a year later, As my passion for the marine increased, I was forced to combine various tanks of fish. Immediately upon placing the pair in with the labiatus, the female quickly(<1 hour) reestablished her bond with the labiatus and they started to beat on the larger, typically much more aggressive male managuensis.

Along similar lines, I've often noticed that if I have to remove a fish due to aggression, It often can never rejoin the community it was removed from, even after reaching full size. They always seem to get beat on relentlessly, as if the others remembered that they were able to "chase it off" before.

Just my experience.
 
I don't think it's a memory of former tank mates that triggers the same response of the fish as before but the actual disposition or "personality". for lack of a better term, that allow the fish to get along or not.

Put another way, the species traits & personality of say a butterfly & tang made them compatible in a specific environment. Even though they are separated for a time, the personalities of the fish don't change so they become compatible again due to the "give & take" that make up these two fish.

Another pair of the same exact species may not get along the same way because they are made up differently & the give & take aren't quite the same.
 
To expand further.............

A tang & butterfly are put together......the tang chases the BF off but the BF isn't so timid that when cornered he arches his anal fin in a defensive mode. They essentially agree the tang is the alpha dog so to speak but that's as far as it goes.

That same tang is put with a BF that is chased off a cowers in the upper corner of the tank. Whenever confronted the BF flees in fear. The tang relentlessy bullies the BF because it allows itself to be treated that way.

If those circumstances are repeated these fish continue to react the same way because it's in their make up.

I'm sure environmental factors, like tank size & other tank mates can effect these responses, but essentially the fish will act the same under similar circumsatances.
 
yes....i had a tang in a QT with a damselfish. The damsel attempted to defend territory and almost got the razor in it's mouth.

The tang was introduced to the display and the damsel was kept in Qt longer.

When the damsel was put in the display - that tang knew exactly who the fish was and chased it constantly. Today its every now and then. The tang does not display this behavior to any other fish (firefish/cardinalfish/clownfish) - just the damsel.

I would say he remembers and payback is a you know what! :lmao:
 
I doubt if they even recognize the same tank. Every morning when the lights come on, the fish come out and spend 30mins just exploring

This is absolutely not true.

My clown pair took to fanning the sand out from the very same rock cave, even after a tank move, all the rocks were re-arranged but they picked their cave out right away.

My female mandarin goes to the same rock every night for it's feedings...sleeps in the same corner every night too.

Fish are smarter than you give them credit for.
 
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