plants aquarium toxic

Can any plant be poisonous to shrimp? I bought 3 new plants from an aquarium yesterday - they were in a tank with snails and shrimp already so there isn't a copper issue, but my shrimp this evening seems to have taken a turn for the worse. Here are my plants

earlier this week I noticed 2 of my peppered corydoras have died. I do have a testing kit and I did test the water and the ammonia was up a little. So I decided to do a water change, did that. Then I took some of the water I had in the tank before water change to the pet shop to see what the...

Hi   I have a 100 litre aquarium containing 6 adult platties (plus 2 x 1cm fry and at least 3 more newly hatched newborns spotted today (argh!)), 1 bristlenose ancistrus and 2 new hatchetfish (more will be added to form a shoal but don't want to stress the filter so adding 2 per fortnight until...