Like you know how dogs can get worms that eat away at the food they intake, is there something like that for fish? Just wondering, and if there is, what are the signs/symptoms?

Hi.

I am not sure what you are refering to?? Heartworms in dogs comes from "mosquitos" not food. However there are intestinal worms or parasites that come from other dogs and environment.
There are bacteria some times in raw meat, is this what you are talking about? And are you having a problem with a food? Or are your fish sick?