My fish keep dying and its a complete mystery to me as to why

[Oceanarnold9585]

I have had my fish tanking going for about 4 months now and although I am quite new to keeping fish I had done a lot of research prior to owning them. It is important to note that about 3 months ago I had what I believe to have been Columinaris which went through my tank and killed all but a few fish, the disease came from my local pet store and they admitted to the fact that they had knowingly sold me exposed fish. I was able to kill it off with a concoction of treatments, but honestly I think what worked the best was hydrogen peroxide. Now 3 months later every week a fish has died with no visible reason for death, they just seem to die at the bottom. The first to go was my young female Micky Platy. The next to go was my male Sunburst Platy. And now I am watching my male swordtail sitting on the bottom struggling to breath (it appears that he is panting or out of breath) and cannot swim. I realize that it is hard to diagnos a problem when you can not see it but if anyone has any ideas I would be extremely grateful. My dad had fish almost 50 years ago and he bred them so I thought his knowledge would be enough but even he is confused as to why I have had so many problems with my tank.

Things that may help you to get a better idea of the scenario
-The tank is a 30 gallon long tank
- It has a bubbler, a under gravel filter and a regular filter
- I have 3 baby blue wag platy´s, one adult female guppy, one male endler, 5 baby guppies, 2 male swords, 1 female sword, 1 dwarf loach, 4 danios, 1 neocardinia. There are also live plants (duck weed, water lettuce, java fern, el nino fern, etc) as well as rocks in the tank.
-The fish are fed every other day
- I have well water, which has sulfur in it (but was never a problem for my dad)
- There is also a snail infestation that I deal with by going in and killing some of them and then feeding the dead snails to my fish.
-the water has some particulates in it but I would not say its horrible

 

[littlefoxx]

Maybe more flow? Also do you treat your water at all for chemicals or the sulfur? Cant imagine thats helping things

 

[saltcats]

Can you post a picture of the aquarium/video of the affected fish?

What are your test results for ammonia, nitrate, and temperature?

Have you added any new fish since the columnaris outbreak?

Sorry to hear about your difficulties!

 

[Oceanarnold9585]

The tank is green purely because I just treated the tank as a ¨just in case¨ measure.
I do not treat my tank for chemicals as I have never seen a need everything that goes in and out of the tank is sanitized (with boiling water) as for the sulfur I could use water from the filtered tap but I feel like if the sulfur was a problem I would have had fish dying the whole time or at least struggling and most of my fish currently are thriving. Other than my two male swords who seem malnourished.
Since the Columinaris outbreak I bought the 3 platy babies, the one female platy that passed away, the 4 danios, the endler and the dwarf loach , I of course waited for two months before I did so though.
The tank temperature stays between 72 degrees F and 79 degrees F.
As for Ammonia and Nitrate I am not sure as I do not have the ability to test for that myself. I will have to go to a fish store for that.