Urgent advise needed on livestock strange behavious

[PupiPupi]

Hi experts,

I need help urgently!
I have a 3 ft planted tank at home which I've maintained for the past year. In it, there's more than 20 rummy noses, one congo tetra, a lot of different types of shrimps (mainly Malayan and Cherry shrimps), 10 pink danios, 4 mini puffers, 6 CPDs, a few corys and 3 gouramis. Of the above, only the Danios are new residents joining the tank a week ago.

About 2 months plus back, the tank plants suffered from a fungal infection and whilst I managed to eradict the problem with some meds introduced by an LFS owner, a lot of the mosses wilted away. During those months, i did not fill up the tank and let the water evaporate till the tank was only half filled. I wanted to clean the branches without having the dirt (or fungus) go back into the tank water. When the fungus all went away and the water was crystal clear, I begin to slowly fill up the tank bit by bit in the span of 3 weeks. I have some lily plants in the tank.

The strange thing happened since Sunday. All the shrimps would swim up and kind of rest themselves ON the lily leaf that's above the water. I will attach a photo below so you can see that the lily leaves are just above the water line. I didn't think much of it until yesterday. All the fishes began to swim at the surface of the water. That is not normal. I thought maybe the filter broke so there's no oxygen. I checked and my filter is going strong. I've since switched of the CO2 supply for a night. Still the shrimps are on the leaves. And there's an abnormal about of dead shrimps on the floor of the tank (like 10 pieces?). They are all fed regularly every night. I really don't know what could be the problem. Can any of you advise?

[PupiPupi]

Sorry I forgot the photo! And also thought I should point out that I did add plants on Sunday (2 days ago).

[chlorophyll]

I am not an expert but did you rinse or soak the plants with water before adding to the tank? Could be pesticide on the plants. You might want to do a 50% water change add activated carbon to your filter . Hope this helps.

[PupiPupi]

I am not an expert but did you rinse or soak the plants with water before adding to the tank? Could be pesticide on the plants. You might want to do a 50% water change add activated carbon to your filter . Hope this helps.

Thanks for your reply Chlorophyll! I did rinse them but did not soak them. Bought all the plants from Seaview and never had such a problem. Maybe the rinsing wasn't good enough. Will do WC tonight and hope that helps. Active carbon are the bags of charcoal in mesh bags?

[chlorophyll]

Yup, if you not too sure just ask the LFS for activated carbon.

Also check your tanks aeration. Is your outlet flow providing sufficient surface agitation for gas exchange? Because plants also consume oxygen after photoperiod. I switch off my CO2 30 mins before lights-off to allow some of the remaining CO2 to be absorbed by the plants and some to be de-gassed. For a planted tank, minimal surface agitation is best to prevent CO2 loss during photoperiod but that also means little oxygen for your livestock during lights off. Some Bros here use an air stone during lights off to solve this.

[Shadow]

did you check your ammonia level? the medication might kill the beneficial bacteria inside your filter