What's with Jack Dempsey dorsal notch?

[luvinbluegills]

I've seen a lot of Jack Dempseys over the years, and one thing that I see regularly in large adults is a big notch in the dorsal fin.

Does anybody know what causes this? I would have simply assumed fighting, but I don't see the same thing with similar frequency in any other medium to large cichlid!

 

[RLHam3]

It
it's probably just from over crowding when it was young. And i don't think that its that uncommon in other species

 

[skooby]

All the jacks I've had don't have it exept one that got into a scrap when young and it never grew back

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[lp85253]

for some reason thats were they end up getting bit

 

[TheNailman]

not at all. i think its hereditary.
my jacks both have it. when they spawned, the young grew out, we rehomed some of them, but ALL of the young we kept have the same notch.
I have no idea what the purpose is, but I would very much like to know if anyone has more information.

 

[Eatsomekiwis]

my male had it too, had him from 2"-9" and the notch never went away

 

[Loves severums]

what notch?

 

[jadedreams]

I have one that has it and one that doesn't, had always thought the notched one had been in a fight. Interesting.


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[bobblehead27]

I too had two brothers and they both had the notch and always thought it was some weird coincidence that they both got bit there and never healed :-/

 

[luvinbluegills]

not at all. i think its hereditary.
my jacks both have it. when they spawned, the young grew out, we rehomed some of them, but ALL of the young we kept have the same notch.
I have no idea what the purpose is, but I would very much like to know if anyone has more information.

No way! I didn't expect that, but I'm glad to know it isn't my imagination!