Please help!

[lifeofbrian]

My fish have been very shy the last 2 days and I have had 3 dead tetras 2 days ago and 2 more today. Today all my tetras look like this.

About 2 months ago I restocked my tank after moving home, all I had left from my old setup were 2 x-ray tetra.

I bought 8 Black Phantom Tetra 1 African Dwarf Frog, 2 Sterbai Cory, and 1 Electric Blue Ram. All fish were shy at first but all came out and really were very active and happy apart from the Ram that wouldn't eat anything, I bought about 7 types of food until he started to love Bloodworm, but he never got his colour back fully, I waited a while but he never seemed to fully recover so I spoke to the fish store and they mentioned worms, so I dosed with "eSHa -NDX Anti Parasite Treatment Treats Roundworms For Fresh And Marine". Followed the instructions did a 50% water change after 24 hours. But after about 4-5 days my tetras were all hiding, so I did another 50% water change(25% was due anyway), 3 days later and now all my tetras look like death, my Cory's and frog look fine and my Ram just hides. I've tested the water 3 times and it all seems great, but I admit I do not have an Amonia test. I'm so upset I could cry. What have I done to my lovely fish?

EDIT:
Tank Specs / 120 ltr tank / cf500 filter

 

[10 Tanks]

Hello. This hobby is 100 percent about the water and keeping it free of dissolved waste material. Apparently, you have a small tank. You've likely introduced too many fish at one time. Your water changes aren't consistent and you've put chemicals into the tank water. The water chemistry is unstable. The only thing I can suggest at this point, is to change half the tank water every few days until you see improvement in the health of your fish. Keep the chemicals out of the water and don't feed for a few days. At the end of the week, start feeding just a little every couple of days and most important, keep up with the water changes.

10 Tanks (Now 11)

 

[Byron]

I won't guess when it comes to disease/health issues, but I will tag a couple members who do know. @Colin_T @GaryE @Uberhoust

You have some stocking issues, but this is not the time to get into that, saving the remaining fish if possible is priority #1. And I certainly agree on water changes...provided the parameters which are GH, pH and temperature are the same, you cannot do harm to fish changing more and more water.

And it helps to post actual test numbers when you do the test, none of us knows what "seems great" means.

 

[Uberhoust]

I am not a disease expert. That said your fish looks to be shedding mucus, looks like a time I forgot to put chlorine treatment in the tank during a water change. I would suggest you have something in the water, ammonia, chlorine, medicines. Water change without anything other than chlorine treatment as long as you follow @Byron notes about matching the water parameters. Your fish will be in a weakened state, when you do your water change really go through effort to match the temp as close as possible.

 

[Colin_T]

The male black phantom tetra in the picture is covered in excess mucous caused by something in the water irritating the fish. It can be poor water quality (ammonia, nitrite, nitrate) or chemicals introduced into the tank from an outside source (something on your hands or sprayed near the tank). It can also be from buckets used to fill the tank after a water change.

The treatment is doing big daily water changes and gravel cleaning the substrate. Do this every day for a week or for several days after the fish look normal again.
Make sure any new water is free of chlorine/ chloramine before it's added to the tank.

Make sure you don't have any perfume, soapy residue, hand sanitiser, moisturising cream, oil, grease or anything else on your hands when you feed the fish or work in their tank.

Make sure you have buckets and hoses specifically for the fish. Get new buckets and use a permanent marker to write "FISH ONLY" on them. Use those buckets for the fish and nothing else. Make sure the buckets are food grade or food safe so they don't leach anything into the water.

Make sure nobody is spraying anything near the tank or doing anything that releases fumes, smoke or odors near the tank.