Petshrimp.com Discussion Forum

I got a 55 gallon with the following

2 Parrot cichlids(breeding pair)
2 convicts(breeding pair)
1 Livingstoni(camo cichlid)
1 pleco

Can I add a couple of river crayfish?

I wouldn't. At the latest when your crayfish molts it will be fish food.

As mentioned by Mustafa, it would probably not be the best idea. The crayfish very well may become food for the fish or vice versa.