I haven't but I thought it was an interesting question.
You can put goldfish in a tropical tank, if they are sized to be compatible with the current inhabitants. The goldfish will eat all of the floating duckweed and Riccia if you want to eliminate it from a planted tank or any tank. They at first will leave most live rooted plants alone, if you have 2 - 3 goldfish, but they will grow over two to three months until they start being a pest in this regard. And that is fine, because after two or three months in a tropical tank, goldfish need to go home. They are like Northerners who like to vacation in the tropics, but when the vacation is over, they are glad to go back. Even the plants, the filters, and the tropical fish will be glad to see them go. Typical filtration for a tropical fish tank will have been maxed out by that time. The plants will at first appreciate the generous fertilizers the goldfish provide, but then there will be a backlog of it. Too much of a good thing does not sound quite right when we are talking about goldfish poop, but if you look at it from the plant's perspective, it does fit. and it may be subjective, but it seems like the angelfish, the kribensis, the red lizard catfish and others seem to be getting impatient with the tourists hanging around past the season. The goldfish definitely need to go back to their own kind of tank, food, and temperatures. Fish foods low or without fish meal,and perhaps high in wheat germ will help keep their digestive systems on track. They will also appreciate the absence of gravel, and the feedings of duckweed, Najas, hair algae, and live daphnia that you raise for them. You probably wouldn't want to add the first three to your tropical tank, and if you add daphnia the tropicals would likely be first in line and deprive the goldfish of more than a sample.
Certainly if a material is reflective, it is not absorbing as much of the laser energy and is not subject to failure that way. The question then becomes, how reflective is the material and how powerful is the laser? There is no perfectly reflective material, so some energy will always be absorbed. That means if you bump up the power of your laser enough, you can always guarantee that it would be destroyed. Then it's a matter of whether destruction in principle is sufficient or whether you have to actually be able to build such a laser.
