I have a platy in a breeder net laying on its side with a bent spine. It's bent like a V, and it's not a birth defect because it just developed this a couple days ago. The female platy I had with it just died two days ago from dropsy out of nowhere. The fish that is bent is a male who has been doing poorly since day one. It has always been on the thin side with raggedy fins. No fin rot or torn fins, just very raggedy. It has always eaten, but never much.
I tried to do a search for a cause, but I'm coming up with either fish tuberculosis or a vitamin defiency. I don't think it's tuberculosis because the fish doesn't have any other symptoms. I don't know much about either though, so I came here for help. The water in their tank is maintained regularly, and the parameters are all normal. This is very unusual and I can't figure out what's causing it. If anyone can help, it would be greatly appreciated. Thanks.

Im sorry to hear about your platy. Livebearers tend to be tough. They sure do have an awful lot of health problems. Ive kept lots of fish through the years but have never had good luck with them.

I have heard of the bent spine before and I seem to remember hearing that sometimes it can actually be due to a poisoning. Do you know what hydrogen sulfide poisoning is? This is very common with koi ponds. Basically it comes from letting your gravel hygiene go for an extended period, and then when you do get in there and stir things up, it releases basically toxic gas that has been building up under there. Some fish die very suddenly from it.

I am not saying for sure that that is the case here but since it came on suddenly it is a possibility. Have you done a water change recently? Do you have an undergravel filter on there? The same can happen from not maintaining UGFs correctly.

Other than that I would say that its possible he has always been a weak fish, and maybe now its just getting the best of him. I really hope you figure this out and hope I could help a little.