Will goldfish eat salvinia? Is it safe for them to do so?

Hey all,

My manager has a single goldfish in a small tank in her office, and I am trying to think of things to encourage her to take better care of it. For the last week it has been sitting in there with water at half full, with nothing in the tank but filter, heater and multicolored plastic jewel things for a "substrate"

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I really feel bad for the fish, mainly because it looks so bored just floating back and forth in there with nothing to do. The tank is a bit too small for it too, but I can't do anything about that, so I have been thinking of things I can do to help enrich the life of this poor goldfish.

I have been thinking I might bring some plants in to put in the tank, but I know goldfish will eat most plants. Does anyone know if eating cupped salvinia will hurt a goldfish, or is it ok to eat? How about Cabomba carolinia? This stuff has really taken off for me, and I will soon have lots of extra.

Any other suggestions on things I can do to make this goldfish happy? I have never kept goldfish, so I don't know much about them. I think I should check where the heater is at too, I don't know how warm it is but it's certainly possible it's too warm for the little guy.