There is so much meth in some rivers that the fish get addicted to that thing.

When fishes are addicted to meth, that thing causes problems with their behavior. The fishes like salmon might not leave their home river as they should. 

If salmon would not go to their hike, that thing can decrease the number of those fish. Addicted fishes are acting like all other drug addicts. All fishes are the addicting same way, so the addiction is similar with brown trout and other salmon fishes. 

They forget to copulate, and another thing is that their weight is decreasing. The fish will also get easier to eat by predators, and that thing can be devastating for the fish and especially the salmon and other stocks of valued fishes. So that thing means that meth is a big problem for the fish and fishermen. 

If the fish would not eat that thing would decrease the earns from the professional fishermen, but also sports fishermen are getting out from the hotels because there is no fish. So, in that case, they must search for a new river for their hobbies. If there is no fish the place is not interested in fishermen. And that thing can cause problems with the economy. 

The addicted fishes can use as biorobots to search the meth laboratories or other chemicals like gunpowder. 

But there is introduced an idea that the meth-addicted fishes can use as biorobots. Those fish can equip with GPS and that helps the operators to capture meth laboratories. But those behavioral manipulated fishes can track almost everything. If things like gunpowder are mixed with the nutrient of the yarded fishes. Those fishes can also tack those things from the water. 

The use of addicted fishes as biorobots, what can search meth laboratories at the rivers might be one of the things, what can be fascinating. In that vision, the fishes, who are addicted to meth would equip with the tracking system. The easiest way is to tie the plastic wire to the tail of the fish. 

The fish can be followed by the quadcopter, which can operate airborne or underwater. And the thing that is enough is that the follow-up operators must do is to separate those addicted fishes from other fishes. 

That tracking system can be the GPS-locator, which is tied to the tail of those fishes. And then it would send to the river. If there is meth-laboratory somewhere the fish would swim to that laboratory and find it. Or it can find the new, where is the meth-source. That thing can help the authorities to find the meth labs. 

()https://futurism.com/research-meth-fish-addicted

()https://www.livescience.com/meth-addicted-brown-trout.html

Image:()https://futurism.com/research-meth-fish-addicted