Odd Question I Have

[afireinside]

I was just randomly thinking today, and I thought of something I couldn't figure out.

Let's say you have a tank full of adult fish. Let's just say angelfish, as that's the first fish that came to mind. They all get along well, and you take one out and put it in a new tank. You leave that angelfish in the new tank for about a year or two, and then you decide it should go back into the tank it came from. Now, all the fish had been together since they were very small (including the one you took out). Would the fish recognize each other if something like this were to happen? I just thought it was an interesting question, and I'd like input on it.

 

[dusky]

I don't think so. Well with my girl Bettas if there is trouble in the tank i bag them all up, rearrange stuff and put them back after a little while so that they all seem new to each other and tank seems new and they usualy forget which one they've been picking on. But maybe different fish vary.

 

[shelaghfishface]

no they wouldnt, i bought 2 angle fish from my lfs, and left one in the tank behind, the next time i went in he was still there so i bought him, they were all very happy and placid in the tank at the lfs, but when i added the last one to my tank all hell broke loose, only for a few days but it it did all the same, but on the other hane my oscars and goldfish, remember who i am so who knows

shelagh xxxxx

 

[minxfishy]

I doubt they would, although like any animal, we cant get in their heads to find out for sure.

I dont think most fish have a particularly long memory?

 

[dthoffsett]

There's no way to really know if they would remember a tankmate. It's really a question of territory, with your successful tank full of angels everyone has their own territories, and have worked out their pecking order. Remove one, and those left in the tank will adjust their territories and hierarchy. When you return the one you removed, the established tank will consider it a rival to their territories and place in the hierachy, so you end up with a fight instead of friends, that's why most cichlid keepers try to rearrange the tank decor before adding a new adult or returning an old one. It doesn't always work though, adult cichlids can be a bit stubborn.

The above scenario would be true for most territorial fish, however, I believe peaceful schooling fish like neon tetras wouldn't have too much of a problem with a newcomer or returning buddy for two reasons. First, there is safety in numbers, and second, with a large group it's easy for the least aggressive members to get "lost in the crowd" from the alpha members.