Sick Platies, Hiding & Clamped

Hi, I have a 29 gallon heated, filtered, tank with 6 adult platies, 2 mollies, 1 swordtail and 1 cory. ammonia 0, nitrite 0, nitrate 0 -5. I do a 30% water change every 2 weeks with prime. I just changed 50% because of my problem.
On and off I noticed some fishes' anuses were white/possibly swollen. It was always the females and I thought it may be because they were pregnant, until I introduced a male molly and noticed his was also white. When the platies came to me in October unexpectedly, I cycled the tank with them for a few weeks then added TSS. One male became weak and developed a red spot near his head. Since then he's gotten better, the red spot got smaller but is still there, until now it seems he's wasting away(sometimes! He looks much healthier today than in the pic that's a few days old). The fish have had some white/clear/stringy poops but I have not seen any worms. Yesterday and today they've been fed flakes & bloodworms soaked in garlic juice because yesterday one female platy with a swollen white anus was and still is unusually lethargic, clamps fins sometimes, has been hiding at the bottom then hovering near the surface, and is barely eating. Two more platies have picked up this behavior today.. please help. A few have flashed & developed white spots so I'm treating for ich with heat and a little salt and garlic food.. but could the other symptoms be camallanus worms or another parasite? Reminder I haven't seen worms but their appetites, poops and anuses seem unhealthy. Thanks

 

I had a problem with camallanus and many of my fish were clamping the same way. My male Molly literally wasted away. Wasting and bloating are both signs of the disease as is inflammation if the anus. It might be something to consider.

 

Giving this a bump up for you

 

Thank you. Any other opinions? I found one of my female platies dead this morning.. I'm going to start treating with levamisol unless there are other suggestions. Ill have to find the meds in store. These are my first fish and besides turning up the heat for ich I've never treated a disease. The swordtail is still only pooping white but they all seem active. The one that died was at the surface and wouldn't eat last night. suggestions?

 

Thank you. One of the platies died overnight. I'm going to start treatment with levamisol that I'll have to buy soon unless there are other suggestions. The swordtail is still pooping white but they're all active now. The one that died wouldn't eat last night and was at the surface