New Hobbyist Needing Help!

[AquaAngelfish]

Hi everyone, I really hope someone can help me out with this!

I'll start with the basics as follows:
I have a 36 Gal. Freshwater Tank.
1 Marble Angelfish
2 Lyretail Mollies (I'll get into why later in this)
6 Panda Corydoras
2 Nerite Snails
(Keep in mind: This tank was started earlier this year in late February/March, tank was fully cycled for over 6 weeks before adding fish. I do water testing weekly using the API test kit, and 40%-50% water changes weekly).

Tank History;
I used to have another angelfish as well, but unfortunately he died to which I assume was dropsy. This was only 2 weeks after getting him, but afterwards everything in the tank seemed just fine. I haven't had any more problems until now just this last week and it's freaking me out about what's happening today...

Last Week's Problems:
I lost 2 of my 4 mollies, both within about a month of each other. (The first one died unexpectedly but was a big bully in the tank to my Angelfish, so I'm guessing something between them happened? Idk. However, I just lost the second Molly about 2 days ago, weird thing is that I couldn't even find her body. Did and entire cleaning of the tank, can't find her at all, but I saw her acting weird the day before her death but didn't think much of it because I had to leave in a hurry that day). But, I did do a quick water test with my API master test kit and everything seemed normal, so I didn't think too much of it, until she unexpectedly died.
Today, one of my female panda corries was acting abnormal, digging her head into driftwood and constantly hurting herself, I've been doing water testing for everything everyday since the molly died, and everything is fine. Today, I did 2 tests, because I thought for sure I had ammonia poisoning, but everything, including ammonia, nitrate, nitrite, etc, is 100% normal. The only reason I'm worried is because all the symptoms I was seeing in both the molly and the panda were pointing to ammonia poisoning/spike, and tests were normal. The chemicals weren't even expired either, I got the test kit in March.

What I've done:
-Corydora is in a little breeding net in my tank, in hopes she won't get as hurt.
-Used melafix just for good measure to help her injuries

I honestly don't know what's going on or what to do. If anyone needs more info on something or can help, I'd be very grateful!

(I just realized how long this was, so thank you for reading all the way through)

 

[Autumnsky]

It is hard to know what is happening exactly.

Have you used bug spray wasp spray, air spray any cleaners in the room or used hand sanitizer lotion bug stray lotions, etc on your hands / arms and maybe not washed it all off before putting your hands in the tank - just checking.

As for the kit you are shaking and following all the directions correctly?

Sometimes it isn't shaken long enough.

Do you know the other parameters.
pH
KH/GH
TDS

Check for the bodies for the fish for any worms spots dots on the body, eyes, mouth, gills, anal vent.

https://www.aquariumadvice.com/fish-disease-index-for-diagnosis-and-treatment/

Future thought would be to make sure you always quarantine fish for a couple weeks to months to make sure they are healthy to be added with the other fish.

If in doubt do a series of water changes to dilute anything which might be in the tank.

 

[AquaAngelfish]

Hey, thanks for your help!

To start off with, I always make sure to thoroughly clean my hands and arms before working in the tank, even if I didn't put anything on my hands. (Without soap, I just use warm water for a few minutes).

For the test kit, I'm shaking the bottles for a while before testing the water, and even after following directions closely and doing it a few times a day now, everything is normal.

My pH is exactly 7.0
6 dKH, 5 dGH
TDS 150ppm (Just got a tester for that today, never knew about it).

The only thing I'm seeing is that on the panda's gills after she unfortunately died this morning was some redness, (No redness before death), and I couldn't quite tell that in the other fish since they were very dark in color. I researched it and it pointed towards an ammonia spike in the tank, which according to my tests I didn't quite have, even a week after not having any ammonia I still lost my 2 fish this week. They both were acting kind of weird for a little bit, not eating as much and running into stuff, constantly hurting themselves.

I really want to help my remaining fish and get rid of anything that's in the water before even considering getting new ones. Sources I've been reading online all say different things about what to do and I'm very conflicted.

Another question I have now too:
Now that I only have 2 mollies, should I get more (after figuring out the problem) to bring up the recommended number of 4, or will they be fine with only 2? I feel bad just leaving them with two, but I've experienced serious bullying with them between the corries and I don't want to have to deal with that again, but I will if I must.

Thanks so much for your input, sorry I have so many questions!

 

[Autumnsky]

Questions make keeping fish easier after getting the answers, lol!

As for the Mollies, if they do not suit your situation then just move along. Do not need to get more fish which you do not care to keep. Yes they do better with groups, but in the future maybe some one may want them, and they can be rehomed. If you happen to be near a Aquarium Society group meeting, maybe someone would want to rehome to them.

If at a previous time the tank had a nitrIte problems, it can damage internal organs and fish can die 2-4 weeks later, or just suffer along for awhile and die fur unknown reason.

For now I would just get the water changes up and really work towards getting a whole new tank of water. long time back I read about how it takes quite a bit longer to change out more than 100% of the water.

Because if you do 25% and then add back that water then do a 25% - You don't actually change 50% of the water in the tank because it mixes and you'd remove maybe half that much??? I can't recall and do not understand thinking back how it was calculated. But bottom line is it might take a persistent number of changes like 10 times to get 100% of the tank water changed.

And see if anything gets better. IF anything got into the water and was causing extra issues, you would be able to change it out and start fresh.

Also as a side thought, water companies add crazy toxic stuff to flush lines, kill certain bacteria and what have you during the different seasons, but also when there are repairs and changes in water sources. You may call and talk to someone who may know if around the times that you started noticing the problems, if they were doing anything different or special. And ask what they ARE using to treat the water and have used in the past X number of weeks or however long it has been.

I lost a large group of shrimp during a water change almost all died 150 of them and called and found out that there had been a change in the actual pipe they used to bring water in to the town, and they flushed the line to kill germs with a much stronger chemical which was indeed deadly for shrimp. The water didn't smell different or look different. But it sure did kill off the colony.

Anyhow you just never know.

 

[AquaAngelfish]

This really helps!!

For now I'll keep doing water changes every few days and see how that goes. Interesting about the whole water sources thing, I'll look into that, too.

As for my mollies, I'll keep them, as they don't seem to mind being in a pair, as from what I've seen. I've noticed that bullying has gone down since I lost the two, but the two I have left still look happy and have normal molly behavior, but I'll see if my local fish store is open to rehoming them if I notice they would be better in a group, if that makes sense. But for now, I'd like to get my whole tank problems under control.

Thank you so much for helping me, I highly appreciate getting non-judgmental answers from more experienced keepers!

 

[Autumnsky]

You are welcome. It is ideal to do what you can for the fish, but it IS hard when you just aren't sure what it is that is wrong.

I hope you can solve the problem with a bunch of water changes.