I'm not sure anymore. 75 gallon tank.

I used seachem stability to restart the tank. After about 6 or so months I got the dreaded blue/green algea aka cyanobacteria. I removed as much as possible then treated with erythromycin. Didnt lose that many fish tbh. Anyway so I'm back on track and my plants look like crap to say the least. So as I'm doctoring everything back to health I see a sale at a certain big box store on neon tetras .99 each who couldn't resist. Well being I have always got my fish from a locally owned place I have never quarantined any fish nor ever had an issue. Well I cheated and then I had ich. So i raised the temp. Added 1.5 thr dose of salt and by the time it was over lost 60% of all my neons. Btw I had 50 of them. Did the water changes for the salt content and lowered the temp back to 78ish. Ended up shortly after with a bacterial infection. Used paraguard to treat and lost all of my vallisneria which was a lot. Now after a month of getting things back to normal I got a few guppies 1 male and 4 female. Now the guppies are prego and some are also showing signs of an issue. In the pictures I'm uploading the super skinny one was kinda prego but then got really skinny. I think she had the babies but I was not prepared just yet so they were dinner. Now she isnt eating and not looking the best and another one who is very prego is got some scale issues Please help.