Plant advice

Ok, so I'm planning on sticking this into my tank, but first I was thinking on getting it covered in moss or some sort of plant (can use the bricks to hold it) but I don't really know what to get.

Any ideas of something that will grow fast (also, how fast?) and cover it nicely? Something that cichlids won't eat.

 

I don't believe there are any plants cichlids won't eat.
Some people have luck with Anubias, which you could tie to the lego and it might attach to it.

 

java moss and some sort of net/mesh is your best bet

 

I'm no fishkeeper person, but doesn't lego float?

 

I had some of that before but it just floated into the filter

Yea, but that's what the base is for. To weigh it down with stuff.

 

That's where the mesh/net comes in.

 

That would look awesome covered in moss

 

"Riccia" would be best. It grows fast and becomes established fairly quickly.
There are plently of tutorials on how to get it established on a rock that would apply in this case