I had a P. cilata (Rainbow Mantis) for 4-5 years known as Chaka prawn. Bright canary yellow and realy cool to watch. I only fed it live food every now and then, and it would readily take small shrimp scraps, silversides pieces, etc. Over a few molts they will change color to blend in with their backgrounds somewhat. Amazingly fast strike! He got to about 4" maximum and would not hesitate to take down the largest cleaner shrimp, etc. But wouldn't touch larger fish like damsels, etc unless it caught them napping at night. I would put in 5 of the cheapest damsels I could find and then slowly over 2-3 months they would just vanish one by one.
We also has a small N. wennerae in a 1.5g pico tank on our bar that we fed scraps and small snails/crabs to.