Plants looks weird after a water change.

[LiveBearerLover]

Using my aquarium coop test strips was reading high level of nitrites. So i did a 50% water change. I dosed the tank with water conditioner while it was half empty and add water from the tap at the tank’s temperature. I had a platy die, all 14 babies platies alive and the mom hanging out on the surface of the tank.
 

The rams seems like everything is fine and I notice a lot of dead bladder snails. What did I do wrong here? I’m so sad because i felt like I was finally coming to my own (dialed in) and all the plants were looking great and healthy. 

Edited August 5, 2021 by LiveBearerLover

[Jungle Fan]

If you had a high level of nitrites it wasn't the water change that went wrong, it would have been something that came before. How long ago was your tank cycled before you added the fish? Nitrite is a blood toxin that does damage to the gills of fish, and destroys their blood cells ability to carry oxygen.

Edited August 5, 2021 by Jungle Fan

[LiveBearerLover]

Thank you jungle fan for responding. I’ve had the tank running since June with real plants. I added 6 platies in July 01, 2021. Testing with test strips nitrate were at a constant 40ppm with easy green. Nitrites were 0. When I added the rams I noticed the nitrites were ticking up since last Friday. The tank is stocked with MTS, bladder snails, 3 ghost shrimp, 3 platies (14 platy babies), 2 green corydoras, and 3 golden balloon rams. Anubias, ton of wisteria kept trimming and replanting , frogbit and wisteria. It’s a 90 gallon tank with co2.

 

Edited August 5, 2021 by LiveBearerLover
Adding more details.

[HH Morant]

When you say you had a high level of nitrites, My first question would be "how high?" 

The tank has not had time to become well-established, so this is probably a hiccup in your cycle. I would do water changes to keep the nitrite level low until your filter develops the bacteria necessary to oxidize the nitrite. If you have access to a seasoned sponge filter or seasoned media from another tank, that could be helpful.

I doubt that nitrites harmed the plants. I am not sure what the leaf discoloration is in the pictures. It could be algae growing on the leaves.

[Jungle Fan]

What you said about the bladder snails might be a clue, although I tend to agree with @HH Morantthat your tank is still not quite established. I presume the bladder snails were hitchhikers, they could have introduced something to the rest of them whenever you introduced the last batch of plants that eventually led to a mass die off which then could have led to the nitrite spike as they rotted, and the nitrite would be what led to your fish dying. Bladder snails are invertebrates and as most invertebrates their blood is not based on hemoglobin, so therefore it was not the nitrite that led to their demise.  That's also the reason why I always introduce snails, and shrimp weeks before I add fish.

Now this is just the most logical scenario I can come up with based upon what you posted, however there could be something that's overlooked. Your MTS are doing fine? No corpses hidden in the gravel?

Your Wisteria doesn't look too bad, I would continue doing more frequent water changes for a while, keep an eye on those snails, and watch how much is being fed.

Are you dosing ferts?

[Patrick_G]

I’m not positive but the Wisteria looks like it might still be at least partially in its air grown form. The  Maybe someone will chime in with a second opinion. Are your Anubias having problems also?