Aquariums are a lifetime passion of mine, and now I have a project I am beginning. I have two established tanks, one is 125 gallons and another is a custom 100 gallon. The 125 has 3, 8" plecos and 1 7" koi. I have a strange request. For my custom tank I am doing an experiment and need a fish that will destroy the tank safely. I'm talking algea, slime, just absolutely nasty. I will be doing controlled experiments on the algae and water. After the tank reaches prime disgust, I will be rehoming the fish to my 125 gallon tank to live a cleaner lifestyle. But I need the fish to do 3 things. 1, it needs to be and happy turning a tank to trash. 2, it will need to fairly hardy species. And 3, it will need to be capable of not killing my KO I and plecos. If I end up needing to buy another aquarium to house the fish alone it can be done. I just need a list of fish that are disgusting in short. Anyone have ideas?