Backyard Aquaponics
A place to discuss aquaponics

I bought my system about a year ago with all equipment and fish as one package deal. I've finally pulled a couple fish out to address the issue of deformed faces and the bumps. Is this from poor water quality, over crowding?
Is this something that is hereditary? Safe to eat then still?

Thanks in advance!





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Welcome to the forum

Anyone have any ideas?

Your current water quality probably has nothing to do with the deformities; fry exposed to various water contaminants when they're tiny and growing can develop deformities, or it could be the result of inbreeding, certain infections in either the fish themselves or their parents, nutrient deficiencies, or just the fact that fish with 'birth defects' that would probably lead to them dying in the wild can survive in aquaculture because the conditions are optimised to produce the highest survival rates possible. I did a little Googling about deformities in tilapia and found some interesting stuff!

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2738889/
- "Tilapia (Oreochromis spp.) were collected seasonally from four contaminated rivers in southwestern Taiwan for studies of morphological deformities that could be used as biomarkers of contamination. Morphological deformities found in tilapia were separated into 15 categories. Overall, the prevalence of deformities such as split fins, lower lip extension and gill deformities were significantly related to various water quality parameters, including low DO and high ammonium, lead and zinc concentrations."

https://www.researchgate.net/publicatio ... _offspring
- This one's funky, researchers deliberately infected a male tilapia with a particular Streptococcus bacteria; it survived but developed deformities, and so did its offspring!

http://www.fishchannel.com/fish-health/ ... ities.aspx
- poor diet or high nitrate levels when fish are fry can also cause deformities

And finally, this link should download a PDF research paper that goes into awesome detail about a whole bunch of causes for deformities in tilapia, shows pictures of a bunch of genetic defects, and also talks about how deformed fish are more likely to survive in fish farms etc:
https://www.google.com.au/url?sa=t&rct= ... KQ&cad=rja

(An extra-interesting thing from that last paper is that the 'stumpbody' deformity looks a lot like some odd trout I've seen pictures of on this forum.)

So yeah! There are a bunch of different possibilities, and if your current water conditions are fine and the fish seem otherwise healthy, they should be fine to eat.

Poor little fella. In that first photo it looks quite self conscious about it

Mel,

Thanks for the links! I'm pretty sure it was from when they were fry. The guy I bought the system from didn't have any plants growing for a while and there were quite a few fish in the system. I tried to separate them into different tanks. I have three IBC totes in the system and for now I've got my beauty tank, my crawdad/yabby tank and then there's the tank for these guys...my special tank!

No worries! I like looking things up. If his water quality was poor and the tilapia were breeding (as I gather they do at the drop of a fin) that would give a higher chance of wonky offspring, yup.