More than likely they are easiest to breed and maintain a pure strain, they know the full genome of the species, they also can probably take more strain from the testing and experiments, etc... Usually your model organisms for certain tests. If it wasn't for tests on these organisms then modern medicine would be bunk, we'd still have issues with small pox, the plague, etc... Cancer and other major diseases that it is more common to survive would be major killers without these tests.
I really enjoyed my bioethics classes because you can see the people that care about the animals and plants vs the people who are just douches and you want to inject them with their own stuff.
Its funny I came across this thread, Just today at walmart we saw the Fruit Tetras and my mom fell in love, cant wait to tell her they are dyed =/ I didnt know that Glofish were illegal in parts of the country too. My walmart and petsmart have glow fish
Yeah, it's so weird. I think GloFish not being legal in CA may have something to do with fears that people will release them into the wild. We have a huge problem with a local lake where someone released pike into and the pike are killing all the native fish. Also a lot of non-native vegetation causing problems, so I think import laws for CA are super strict now. For that same reason, a lot of aquatic plants that I want can't be shipped here either. :/ Sheesh, I couldn't even order blueberry plants from a Burpee seed catalog. They were cool, pink blueberries and I haven't seen the plants offered anywhere but that catalog either.
Ya, we have a problem like that where we live where someone released a snakehead fish in a local lake and it turns out they could walk on land for short periods of time and populates all the local water bodies :/ and did I mention they Are super aggresive? They kill everything!
Oh yeah, I saw an episode of River Monsters on the Animal Planet channel that was about snakeheads. People actually were afraid the things could eat their kids. Fortunately they can't but they can eat pretty much everything else like you said. And what's creepier is they're legal to sell if they're on ice because there are several Asian cultures that think snakehead blood is some kind of curative/aphrodisiac. So all these shops in Florida were selling them half-frozen knowing full well the snakehead was still alive. Apparently they have a high resistance to being frozen.