Virus protction - Mac

[Bud Angelotti]

I know this has probably been addressed before.
I'll throw it out anyway.
Whats the current state of affairs concerning using virus/malware protection on a Mac, running El Capitan? Opera seems to be the browser to use at this time, maybe Firefox.
It's a recycled, Macbook pro. I added an SSD.
Bought this 8 year old MBP so I don't have to upgrade all my needed software. $$$

Thanks in advance!