Multiple fish dying a day. No symptoms!!!!

I have a 40 gal community tank. I wake up to find at least a few fish dead everyday. I found a platy that looked like she might have had a cut on her and maybe got infected and died. So treating with melafix. Ammonia0 nitrites 0 nitrates 20. Mollies guppies Corie's 2 angels betta platies shrimp. They have had no symptoms,all look healthy no acting odd or anything. Just dead!!! Helppppp!! Should I try pimafix too???

 

How long have you had the fish?

 

How many of each fish do you have and how long have you had them for?

 

2 guppies 4 platies 3 mollies. Oh and 4 neon. I think 3 Corie's left.
I just got some last week. I'm sure one of them brought whatever bu t Idk what it is! I started the melafix 3 days ago. Deaths stopped. Then had 3 dead again this morning

 

You also mentioned 2 angels in the first post, right? And do you have one betta? What other fish died besides the platy and corys? Have any of the fish shown any aggression towards the fish that died?

 

Yes 2 angels one Betta. Nope, no aggression at all. Mollies have died and guppies .... That's why I'm so perplexed

 

So, if there are no symptoms on the fish, why are you treating with melafix? Also, I've read melafix is harmful to fish with labyrinth organs like bettas but someone else may need to confirm.

It is possible that the new fish you introduced (the corys?) may have brought something in but if there were no symptoms, I don't know if that's the case. Did you spray a chemical near the tank? Have you done anything differently to the tank like add an additive? Did you maybe forget the water conditioner during a water change?

And what test kit are you using?

 

How hard is your water? Ph? Livebearers like hard water so maybe that's why those are the only ones that have died?

 

The only thing is weeks ago the prime was making my tank cloudy so I went back to the tetra brand , it cleared right up. I'm using melafix bc one of the platies that died had a mark on it that I thought might be a bacterial. My Ph is 7.2 and hardness I'm not sure, I know it's really hard out of the tap. Betta was dead this morning. Ugh!!!

Also, haven't heard that about melafix... It's all natural tea tree oils isn't it?

 

Also, haven't heard that about melafix... It's all natural tea tree oils isn't it?

It's an ingredient in the oil I read that is harmful to labyrinth organs. Flowingfins or Aquaphobia may be able to confirm.

This was a thread I had come across before.

 

It's true. Tea tree oil can be harmful to the labyrinth organ.

"All natural" does not guarantee "all safe" I'm afraid.

 

Well glad I know that now. Separated until TX was done knock on wood no deaths in 3 days. Just did a big water change and everyone seems happy. Fingers crossed. The same day I had a tetra swimming in endless circles. Thinking its swim bladder. It's in a floating hospital tank, not sure what's gonna happen. But 3 days strong so far!