Help! My Zebra Danio Has A Bent Spine....

[Deisler]

Info on tank:
120L with 5 zebra, 1 gourami, 2 guppy 6 cherry barbs 6 neon tetra
this tank has been run for 1 year.
 
5 zebra danios were in the tank since the first day.
 
They lived happily and were very healthy and hyperactive!
 
Water parameter: 0 0 15-20, with DIY CO2 from yeast.
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This morning, I found one of my zebra danios got a bent spine to the side (not downwards). It really shocked me but he/she was still swimming and eating. There are NO other symptoms like sores etc... Other fish looked fine.
 
I did try to google this and I found 'Fish TB' (but all with bent spine downwards??). There are also other things mentioned like 'genetic problem' or 'scoliosis'
 
I dont have a pic right now but could you please let me know what possibly happened to my danio?
 
Thank you!
 
Deisler
 

 

[Bazouteast]

Hi   My guess would be the bent spine is a sign of a genetic defect, becoming more apparent as the fish grows. In the last 6 months I bought and bred a batch of Zebra Danios. I had about 100 fry, and within 2 or 3 weeks it was apparent that around 25% had visible physical defects - mostly bent spines. A couple had very distressing deformities where tissue growths appeared from the fishes' vent - like protruding intestine or other organs. Also there was one with a deformed gill cover.  Another 25% of the fish died within a few weeks because they had swim bladder defects and were unable to swim up and compete for food or because of invisible defects which I suspect are related to the nervous system, where some fry developed erratic movement. Of the remaining fish about 20% show a mild physical deformity - mostly a slightly distorted spine, but not enough to warrant terminating them.   I was quite upset by this so I spoke to the fish retailer - a long-established dealer, and he agreed it was probably down to incessant in-breeding by commercial suppliers. One phrase he used was "How hard can it be to introduce new stock from time to time?".  I raised a question in this forum some time back, asking if anyone knew if all UK Zebras originate from the same commercial supplier. If so, then little point shopping around for 'clean' breeding stock.   I'm not a geneticist so I can't say in-breeding is definitely the cause, and my a fish-keeping experience is significant and as far as I know (and hope!) I have no deformity-inducing fish-keeping practices. So my money is firmly on genetics as the reason.