Originally Posted by jsmith
Does anyone know a rule of thumb such as food must be gone with a minute, two minutes etc?
It's hard to guage exactly what the number is, but the suggested diet quantity for the long term health and happiness of your fish is 75% of satiation. (That goes for humans too). Satiation basically means: to satisfy (an apetite or desire) fully
Some fish need to be fed more often, others are adapted to less frequent feedings. If you feed daily it's a good idea to give your fish regular breaks from feeding. A day off from eating once every week or two will allow their digestive systems recuperate and will be benificial to most fish.
All this advice is general, and specific fish may have different requirements.