Bacterial Infections Decimating my Nano Tank

[desolesiii]

Hey, everyone. 

PH: 7.4

Gh: 10

Kh: 4

Ammonia: 0

Nitrite: 0

Nitrate: 20-40 (33% WC whenever it hits 40 ppm)

The aquarium is unheated, but ranges from 70° - 74°.

 

I have an intermediately-planted 10 gallon tank, and it had 16 Celestial Pearl Danio (which were juvenile when I got them from Aqua Huna about 6 weeks ago); 5 Habrosus Corydoras; and Blue Dream Shrimp.

I got all the fish around the same time, and just quarantined them in the same tank with Maracyn, Paracleanse, and Ich X. At the end of the week of them soaking in the meds, I started feeding them frozen daphnia. I carefully monitored the water parameters, and although the nitrates once briefly exceeded 40 ppm, I never saw ammonia or nitrite. After the second day of quarantine, the smallest CPD (still fry with its yellow stomach visible through its body) was found floating upside down with white fuzz occluding its mouth. This was the only CPD that died initially. Because the CPD's were so tiny, it was really hard to get them to eat at first but eventually the frozen daphnia were the first thing they started eating well. However, a lot of frozen daphnia got sucked into the sponge filter. When I cleaned the filter, I noticed that a lot of old frozen food was coming back into the water. After about a week, I noticed my largest CPD hanging out by the top of the tank gasping for breath. I'm inclined to say that it was pineconed from dropsy but the fish was so tiny, and I'm inexperienced, so my report has little probative value. However, this was the start of an onslaught in which the CPDs started dying one by one. I woke up one day to find the shrimp and the corys eating another Dead CPD. About three days after I saw this (which was today), I found that one of the corys has a bulging eye. Another couple of corys have gils that are very red. (These are likely not ammonia burns since ammonia is 0). I noticed the corys today and immediately added a pack of Maracyn. When I did this, a few of the CPDs swam up the surface and started gasping for breath. Two died after I both added Maracyn and increased the air flow to the sponge filter. I took every fish out earlier tonight and soaked them in a gallon of water with a tbsp of kosher salt mixed in (soaked for 10 minutes before they started settling to the bottom). I have about 6 CPS and 5 Corys left at this point. I put them all back into the tank. No deaths yet, but the night is still young. My plan is to add another pack of Maracyn tomorrow. 

At this point, I'm pretty sure that I'm going to lose everything except for the shrimp which seem unaffected. So, here are the questions I have. 

(1) Before I noticed mass die-off, I moved some rotala from this 10 gallon tank to my main tank. 😕 I soaked the rotala in a 5% bleach solution for about a minute, and then again in tap water before I made the switch. At the time, I had snails in mind, but to what extent should I be worrying about the main tank at this point? 

(2) If I ever want to have fish in my 10 gallon again, what should I do? 😕

I'm pretty new to this hobby, so I appreciate any insight you have. Thanks. 

 

Donny 

[desolesiii]

Oh also, two days ago, I thought I noticed ich on the CPDs, so for each of the last two days, I have added 5 mg of Ich X and have done a 33% water change.

[Colu]

Frist add an extra air stone and then I would treat with maracyn for the popeye and ich x the reddening of the gill can because by ich parasite in the gills