Renowned "tank busters" their biggest problem has already been stated, they grow big and fast, and as you need a group, they require large quarters. In a big enough tank, they are very active but peaceful as long as the other tank occupants are to large to swallow - they are not aggressive, but like most fish, anything small enough to fit in their mouths will be simply regarded as a food item with no aggressive intention.
To fuel the rapid growth, they are "keen" eaters and care must be taken to ensure other fish in the tank get something, the Tinfoils are fast and attentive when food is around. They will eat pretty much anything, and a lot of it.
Also mentioned already, lawn mowers when it comes to plants.