Hi matey,
My indoor tank's empty at the mo, they were put back in the pond because they out grew the tank....then I lost the poor little uns to a fungal infection which I think was bought on by fluctuating water quality, the pond filter had to be cleaned out as it was full of soil
but yes they did trash the plant life when they were in.It didn't bother me too much though,I had a good supply of oxygenating weed in the pond to replace what was damaged.I tried taking it out for a while but it made the fish spooky,they liked a bit of cover to dart behind and the tank looked too bare without it.
There were no survivors of this years spawning so I dont have any to grow on,i'm keeping my fingers crossed that next years better for them.