Rasboras With Tops Of Fins Missing...oh My

[Faythee]

I added 7 Jumbo Rasboras to my tank approx. 6 weeks ago.

A couple days ago I notice 3 of them have the tops of their dorsal fin GONE. Doesn't look like finrot, but as if they were chomped on !

I have a small Angel, Gold Ram, and 3 Diamond Tetras with them. The Angel is shy, peaceful and the Ram just a happy guy. I am thinking maybe the Diamonds, or they are nipping each other ?

Whenever I watch the tank I see the Rasboras darting at each other at times. The Diamonds chase each other. Other than that I don't have a clue *shrugs*

 

[kevin007]

I had 13 harlequin rasboras once and they died off one by one until the last dominant one was left.

 

[Anguilla82]

My guess would be the diamond tetras. Almost all tetras have a nasty habit of fin nipping.
generally if tehy are in a large enough shoal they just squabble with themselves but as you only have three i assume they are taking their aggression out on the other inhabitants. I'd watch out for your angel as tehy are likely to nip at its long fins too.

if you have the tank space i'd suggest adding to the shoal of tetras.

 

[Faythee]

I've been peeking around the corner at them, LOL, and caught them in the act. They are doing it to each other ! I read they have a strong pecking order. Apparantly these 3 are at the bottom of that order. Poor things !

 

[kevin007]

I've been peeking around the corner at them, LOL, and caught them in the act. They are doing it to each other ! I read they have a strong pecking order. Apparantly these 3 are at the bottom of that order. Poor things !

As I've said before, I was only left with one harlequin, the most dominant one, you might be experiencing the same thing.

To the other poster, any chance Cardinal tetras share this behaviour? They ARE a family of the piranha.

 

[Corleone]

All tetras can get nippy sometimes, but some are worse than others. I imagine cardinals will nip among themselves - if you've ever seen the long finned neon tetras, their fins are almost perpetually tattered.