which has more protein...

[vtnamezeboi]

one raw prawn or a small goldfish (2 inches maybe)

 

[kmuda]

I'd say the prawn, especially if fresh.

 

[JardiniBoy]

I'd say the prawn, especially if fresh.

I agree, but I don't think freshness has anything to do with protein content. With prawns there's also less chance of transmitting a disease to the fish, and they're much less fatty .. a much better option IMHO. They do make the water dirty though, so make sure you have adequate filtration and do regular water changes.

I feed my big tank 30 - 50 large prawns every week, amongst other things...