"Evolution is not a fact, it is simply a idea."
No, it's a fact. We know that alleles change in populations over time, and that's all the evolution really is (really, look up the definition--that's it). As a bonus, we've observed speciation, both in the lab and in nature. I'm not quite sure how...
Yes, a quarantine is necessary.
"*If one fish sick rest of them has been contaminated."
First of all, that's not necessarily true. You can pull a fish out before the pathogen has a chance to spread if you catch the symptoms early enough. Some chance is better than none at all.
Second of all...
Buyer beward--most of your answers suggested freshwater animals. Swimmer dude gave you the best advice, so I won't reiterate all of his points, but I'll append his list.
Different people have different experiences with Phosban; some find it useful, others don't. It won't be a guaranteed cure...
...and at the same time, there are people who are certain that the Rapture is coming because they're convinced that the disasters of the world are getting worse.
Fact: catastophes always happen.
Fact: not everything that is said to have happened must be true.
Fact: not all facts of past events...