I would agree that freshwater crusts are better than freshwater fish as food, but even enriched they just don't seem to be enough. When in desperation we tried (during a period of particularly nasty southerly storms...couldn't get the boats out) we noticed increased incidence of fungal infections, lethargy, dulling of colour and eventually increased mortality....especially in our midgets, bobtails and seahorses. We now try to keep at least a weeks worth of marine crabs etc in holding (usually more), plus amphipods, krill (in season) and mysids.
I certainly will not continue with the freshwater stuff as soon as my fiddler crabs get here and I have a free day to go to the beach and collect some shrimp and crabs. I would also love to secure some saltwater guppies from octopets if they are available. I also will get rid of the fish. He got along fine with my octo but maybe he is startling Sally and chasing her food. Thanks for the help everyone!