Poor thing, and it's my fault

Some time ago, I picked up some fish food, and since I have seven goldfish, I naturally got goldfish food.

I forgot about the one surviving platy.

Livebearers tend to eat herbaceous food. Sometimes you can find food formulated for them, but if all else fails, tropical fish food is better for them than goldfish food. Meanwhile, I don't think tropical food would hurt goldfish; it's just more expensive. Now he's got a swollen swim bladder and he looks like his spine is crooked. I'm pretty sure it's a nutritional thing. I don't know if it's reversible, but I'm going to pick up some of the right food and start serving a mix.

:(