Series of deaths

[sheeps]

Over the last week or so, I've lost 6 fish, one every couple of days.


Tank is fresh water with splashes of aquarium salt; running for 8 months.
PH 7.0
Amm 0.
Nitrate 0.
Nitrite 5.
Temp 26C // 78F
Tank is 170L == 45Gal
2 weeks ago I had 4 male Balloon Mollys, and 6 females, as well as 3 juveniles. I've got another two Honey Dwarf Gouramis

Apparently healthy looking fish have been dying rather regularly, and now I have 3 females, 2 males, and 1 juvenile left. One of those males is upside-down in isolation and with my track record, will be out within the next few hours. One of the gouramis is lethargic, but is at least responsive.


My PH has slowly shifted from 7.5 to 7 over the last few months, and I had a small ammonia spike a few weeks back (0.6-0.8) because I overfed them (flakes) during the Holidays. The male who is now in isolation started swimming vertically, which I guessed was a swim bladder/constipation thing. I was advised to fast them all for a short while, and then feed them peas and spinach.
Even after a week of fasting though, they were all reluctant to touch anything green. They pick at the spinach, and the juvenile is the only one who goes near the peas. The constipated one returned to normal after the week, and I've since returned to feeding small flakes in small doses, grinding them into small pieces, soaking them beforehand. Also giving diced, boiled spinach, which they are more likely to graze on once it sinks to the bottom.


I did routine daily water changes for the first week after I had the ammonia, and the water quality has remained stable ever since. I don't know if anything that I can test for is the cause of the trouble... Because regardless of the water changes and such, every few days I'll come home to another Molly sunk to the bottom of the tank, belly up and lifeless.

These fish are generally, absolutely fine and showing no signs of stress or ailment. They just seem to spontaneously die. They're all from different stores and different generations. Of the ones that are left, the healthy (?) male is the eldest and largest. Two of the females I bought 7 months ago, and the other 2 I got early December last year.


So yeah, I dunno. Potential causes or diagnosis I haven't tried? I am extremely discouraged at the moment, so any, any help would be appreciated.
Thanks guys.

 

[Sniperhank]

A good place to start would be the nitrites, as they are poisonous to livestock. You want ammonia and nitrite levels to be 0 at all times. This is basically an issue with not properly cycling the tank that is killing off your livestock.

 

[carey]

I 100% agree with sniper, the fact that you have a nitrite reading is a huge red flag. I would also suspect the tank was not properly cycled as you generally only see nitrites while cycling.
If this is a new tank you also seem to have gotten a few fish too many, gotta go slow and take your time when stocking, whether it's freshwater fish or saltwater fish.
I would do a bunch of water changes and hopefully you can sort out the nitrites through them. Then I would let it ride for a few days and test again. You want ZERO ammonia and ZERO nitrites. Nitrates can be present, not optimal but not as deadly as the first two substances.
Good luck.

 

[sheeps]

Ughh wow I'm stupid. I didn't mean to post this in saltwater... Yeah, my mistake. I put the wrong values for each one too. Not a good night for me last night.
Nitrates are 5, and I haven't had any positive Nitrite readings since I started testing the water a few months ago.
Should have caught that when I proofread :/



Male Molly was still alive when I got back home today, though he's still upsidown. He doesn't eat when I try to handfeed, but I left spinach and peas with him when I left thismorning, and when I came back they were gone.

Went into the LFS and the guy I talked to didn't really have many suggestions to add. I needed new conditioner, I've been using Nutrafin conditioner and he suggested I try Seachem Prime because the bottle says it does more things and it cost twice as much.

So added that today with my waterchange and now all the plants, decor and snails have little bubbles on them.


Thanks guys for your responses, though I guess because I messed up with my original post, it kinda changes the solution a bit. It won't let me edit my original post lol, so if anyone has further advice, I hope you trawl through the whole thread first ;w;