Plastic fake plants are bad for any fish really. Silk plants are a little better because they are soft and don't harm the fish if they swim through it.
the best plants are live ones.
I have Java ferns in my tank as well as the amazon sword plant and the water sprite. You'll need to replace any current bulbs with bulbs meant for live plants however.
**Edited for more information**
I'm sorry but Planted is wrong. And I speak from recent experience.
it is not true that a plant will adapt to any kind of light. There is a big difference between natural sunlight and the light bulbs you have in your lamp.
If you place a plant that needs sunlight under your lightbulb, and the same plant on the window sill near natural light... you will see which one thrives and which one will die quicker.
its the same with aquarium plants. in nature they get/need different levels of natural light. (the Java fern needs low light, the sword plant is moderate, ect.)
since it's not recommended that you allow natural light into a fish tank, you have to suppliment it with some sort of light that will feed the plants...
while they can survive for a time with the normal light that comes with the hood of your tank... they won't last as long as they would if you had a special plant specific light, and you'll be constantly replacing the plants.
