[Diomedes]

Selcon is only useful if you are feeding poor food, IMO. Plain frozen brine shrimp (the equivalent of potato chips) or other crappy fare need selcon, especially if there is little or no variety in the diet. BUT if you are feeding a variety including mysis, ocean plankton, HUFA brinies, squid, raw fish, shrimp etc. then you don't need that stuff IMO. Selcon is just useful in an attempt to enrich already poor food or a diet low in variety. Also, if you are selcon-soaking food that is already high in the ingredients found in the solution, very little of may be absorbed, as absorbtion needs a concentration gradient? (Just a possibility) I have kept my fish fat and healthy without it...
But as my friend Achilles would say, using selcon may give your fish that small advantage that makes them more healthy.