Threw up Worms

[Jessdino]

Hello! About 2 weeks ago my Axolotl spawned. Since then my axies have been kind of off. Noticing some shedding skin on my melanoid a couple days ago we did a water test and the Nitrite was through the roof! We did a 25% water change and then fed them their dinner. When my roommate got home from work she noticed they had thrown up their worms. They were half digested and it was pretty nasty. The water smelled a little off too. We did a much more thorough clean of ther tank today to get out any remaining slime from their decor and eggs hidden in the sand along with another 25% water change. The nitrite is still high though. My albino had calmed down. She ate another worm today! Hopefully she won’t throw it back up but my melanoid won’t eat. He takes interest in the worms and bites it and yanks it from my hand, but then spits it back out. I’m worried now! Any idea what this could be! Is it just the Nitrite issue? I’ve never had a water problem before. I’ve had them for almost 9 months and literally never had heir water do this so I’m not sure what to do! Could it have to do with them spawning? Did that foul the water? How can we resolve the Nitrite issue?