Neon Tetra White Fungus

hi. I am a beginner fish keeper! I have a 250l fish tank purchased from eBay 2 months ago, already stocked. When the tank was moved, we retained enough water in the tank to keep the gravel immersed and the filter also remained immersed in tank water for the move.
The fish that came with the tank were....

- 1 x marbled Molly
- 1 x panchax (there was also a baby but this has recently disappeared presumed eaten!!?)
- 3 x gold barbs
- 2 x glass catfish
- 1 x angel fish
- 1 x moonlight guarami
- 1 x Cory catfish
- 5 neon tetras
- 4 penguin tetras
- 3 cherry barbs

I have since added 2 more neon tetras, 4 rummy nosed tetras, 1 more Cory catfish and 4 Santa Claus swordtails.

I lost 2 of the sword tails for reasons unknown, 2 neon tetras (one unsure why, the other with a large white fluffy growth on mouth) and one of the gold barbs just last week who looked like his mouth was being eaten away.

I have 2 other neons with fluffy white growths which they have had for about 3 weeks. One has it on his fin, the other on his bottom lip. The white fluff dosen't seem to be growing, but I have now treated the tank with pimafix for 12 days with a 25% water change after 7 days and the growths are not getting any smaller either! I don't have an isolation tank to put them in.

I struggled with nitrate levels when I first took on the tank....The previous owner advised that he had never in 15 years of keeping fish vacuumed the gravel, and had never lost a fish as a result. Everything I read/learn about fish completely goes against this! I initially vacuumed every week with a water change whilst nitrate levels were high.....now they are down, I am water changing weekly, vacuuming every 2 weeks. I would like to get some more fish but don't want to if the neons have something that they will pass on to new fish.

My current levels are:
PH 180 (we have very hard water. Can this be the cause of any of my issues? Any advice how I can bring levels down??)
KH 40
PH 6.0
Nitrite 0
Nitrate 0
Ammonia 0

Any advice about how to deal with the tetra growth problem and anything in addition considering above info which would be helpful to a new fish keeper!!!

Thanks very much!

 

I don't have time to read the whole post but I can already see that you're having issues with your stocking. Tetras and Barbs are more cold water fish whereas the swordtails and Cory cats are warm water. Tetras are a lot more docile and passive and Barbs are a lot more aggressive. They are also schooling fish so each one of those is most comfortable when there's at least six of them, except the Cory cats they're happy with three

 

Ok, thank you. Other than the recent additions, the fish all came together so I guess I need to deal other them as best I can now! Other than the mysterious disappearance of the baby panchax, they appear to be living harmoniously as far as I can tell.
Do you have any advice on any further new additions I can introduce to make a happier environment?
Do you have any advice regarding the tetra fungus?
Thanks.

 

The fungus needs a treatment. If you don't have invertebrates you can try copper. I believe maracyn either 1 or 2 should work. If you use then in succession it's the most aggressive treatment to offer. For immediate results you can try 1tsp normal store bought peroxide per every 10 physical gallons of water in the tank. Meaning that a 30 gallon tank probably holds 17 gallons

 

Could it be Columnaris instead of fungus.
Try to.make decent shoals insted of a collection of individuals.