Assuming Red Swamp Crawfish are native, which they probably are in Florida, they are a great addition to the pond. A diverse ecosystem is usually more robust than one approaching a monoculture. Crawfish, frogs, ghost shrimp etc all diversify your ecosystem and food chain.
Crawfish are valuable forage, especially for LMB. A positive addition to your food chain.
They, like redear sunfish, eat snails. This reduces parasites in your fish.
They also eat crud and cleanup carion etc.
Here in Southeast Texas they are sold live in 35 lb bags in grocery stores. Crawfish season is coming up soon. Prices drop later in the season. There are also farms where they can be picked up directly.
