Please Help Me!! My Fish Keep Dying!

My Platy that just died seems to have white gills. Is this fungus that can be cured with marineland ick remedy? Is it contagious? Because my fish have been dying one by one starting when I got new fish on January 7, 2018. The fish that died today was not one of those fish.but most of them that died were. I kind of dissected her a little bit, and her insides were really hollow, and when I squeezed the body the tiniest bit, the body popes open, and a bunch of stuff came out. This is very upsetting to me. On one of my other fish that is still alive, I've noticed what looks like camallanus worms sticking out of the fishes butt.

Ammonia 0
Nitrite 0
Nitrate 2
Ph 7.5
Very hard water.

 

Can you send pictures?

 

I already threw out the one that died, but I can take pic5ures of the remaining ones.

 

Good

I would think the ick medication is only for ick. Yes, fungus is contagious. Most likely the new fish were sick. I'm assuming they weren't QT.
Don't medicate until someone identifies the illness. It could make things worse.

 

If you have camallanus, Levamisole is the cure. Look for Prohibit cattle drench on Valley Vet if you are in the US. It comes in a 52g packet for about $20 - $25 bucks. 1/4 tsp will treat 100 gallons so it goes a long way. I simply divide 1/4 tsp into ten equal piles (simply by eyeballing it). Each pile will treat 10 gallons. I combine as necessary from there - 3 piles for my 30 gallon, 6 piles for my 55 gallon, etc.
Here is a great link for information:


Make sure before you treat. I do not recall white gills when my stock was plagued with the nasty little buggers.
Upload pictures as soon as possible. Unfortunately, many of us have learned the lesson about quarantine the hard way. Because of camallanus worms in fish and chytrid fungus in frogs, I now do a stringent quarantine process that includes treating with Levamisole.

 

I would post some pictures for us, and in the mean time do a massive water change of something like 50% or more if possible.

Also what size is the tank there can be many underlining problems. My guess they were sick from the start but we are useless without more information. : )