My Equipment!

ive never had any problems keeping piranhas, they are very tolerant to mistakes and will survive almost everything, i think you porbably will not have any diffeculties to keep piranhas. just do what you do with every fish.

piranhas are much easier than keeping marine fish. like vampor said, they will tolerate a lot of things. keeping tetras is harder for me than piranhas.

set the tank up just like you do for marine. no need for the skimmer in fresh water fish.

Piranha handle change better than most fish. They are pretty tough. Sounds like you have the basis for a nice setup.

You would certainly want a decent skimmer for the marine setup. You would need decent lighting if you were to go reef. The skimmer would probably cost a fair bit to handle that size of tank.

You are good to go for freshwater and Piranha. A shoal of about 6 Pygo's would be good for their.

Saying that if I were you I would go marine and get a porcupine puffer. But thats just me and there is still a lot of expense to make it marine. Not to mention a lot more to read up on.