I have just got back from Tenerife where I had been snorkeling. I hadn't been in too long when I spotted a Puffer like fish with the same colour and way of swimming. It didn't have any large patterns but was the normal light olive/green/ beige colour. It was more diamond shape with a more pointy face. It did though behave much like a Puffer manner.
Also, if anyone has any reference to identify fish from this region then I would appreciate if they could let on as there was a god variety there of Marine fish and it would be good to know what they were.
I was staying in Los Cristianos and recommend the south side of the beach for snorkeling.
-Jerry