I have just recently moved the LMB and RES from the 55 gal aquarium to the pond. In their place I trapped about a dozen 1"-3" GSF. It took about 2 days for them to accept artificial food. Within a week they became voracious feeders. Now almost a month later, they swim to the glass when I approach and would eat every 30 minutes if I would feed them. GSF are very aggressive fish. Once they recognize something as food they go for it. Even the 1" fish mix it up with the 3" when food is present.
They seem to prefer the sinking pellets (right now that is a small soft pellet from the aquarium shop) but will take some of the floating pellets. They seem to like it falling more than from the bottom, but they will eat pellets from the bottom. I doubt that you will have any problem with them eating artificial food, especially in an enclosed area.
I have really come to appreciate these fish. They are very attractive. Mine show quite a bit of variation in overall color and markings, as well as variation in body shape and fin shape (tail shape mostly). Some of the GSF are almost black in color with very subtle vertical barsand some are more light colored with more distinct vertical bars. It is interesting to see the markings change in prominence when the fish are excited as in when showing aggression or at feeding time. There could be some cross breeding with BG that would explain the variation, but the BG were only introduced into the pond last summer (June-August). The GSF have been in the pond (in stunted form) for years.
I cursed them for years as vermin that had infested my pond, but I think I have come to better appreciate them, especially as an aquarium fish. It is really entertaining to sit and watch them at night after everyone else has gone to bed. They are attractive, highly animate, and very easy keepers. I am still not too keen on them in my pond, but I can certainly see the attraction one might have for them.
