Urgent: Saving My New Tank

So I am trying to start a freshwater community tank with my girlfriend (who has no prior fish experience). We bought 5 mollies and 10 minnows yesterday. 4 of the minnows and 1 of the mollies had died as of this morning. When cleaning them out of the tank (I assumed the minnows just hadn't been super healthy in the pet store), I noticed that there were baby fish in the tank. Since they were actual fry and not eggs, they are clearly mollies. Of the mollies left in the tank, two of them are hanging out on the bottom of the tank. Are these two pregnant as well? Having done some research, I'm afraid the mollie I thought was dead was the one who had given birth but too late to do anything about that now. What should I do? I know mollies cannabilize their young sometimes.

 

HI and welcome!

What size is the tank? Did you cycle it prior to getting the fish? How did you acclimate them when you brought them home? Do you have any plants or decor in the tank?

 

HI and welcome!

What size is the tank? Did you cycle it prior to getting the fish? How did you acclimate them when you brought them home? Do you have any plants or decor in the tank?

It's a 30 gallon. I did cycle it prior to getting the fish. I floated the bags in the tank for about an hour or so then let them swim out of the bags by themselves.

 

How did you cycle it? Did you mix your water into the bags to slowly get the fish used to your water or just dump them in? Did you add the store water to your tank? Do you have a test kit?

 

How did you cycle it? Did you mix your water into the bags to slowly get the fish used to your water or just dump them in? Did you add the store water to your tank? Do you have a test kit?

I cycled it using little bits of fish food. yes I mixed the water into the bags slowly and added the store water to the tank. I have a test kit. the only number that was kinda high was the water hardness but nitrates, nitrites, pH were all fine

 

What test kit do you have? Do you have an ammonia test? What were the exact results?

 

No, I do not have an ammonia test. I use a 6 in 1 test strip.

 

Sorry to interrupt your back-and-forth, but a word of advice, but you said you added the store water to your tank, and you should NEVER add the store water to your aquarium. Store water is often full of parasites or bacteria and diseases that will just make your life difficult.

It is often inevitable that some store water get into your aquarium, but always try to reduce this amount.

Also, you should consider getting the API master test kit. It is the least expensive accurate water parameter tester. Includes pH tests, ammonia, nitrite, and nitrate.

The strips are not very accurate.

 

Sorry to interrupt your back-and-forth, but a word of advice, but you said you added the store water to your tank, and you should NEVER add the store water to your aquarium. Store water is often full of parasites or bacteria and diseases that will just make your life difficult.

It is often inevitable that some store water get into your aquarium, but always try to reduce this amount.

Interesting...I always heard that helped the fish adjust better.

 

Ammonia could be your problem, but also test strips are inaccurate. I would go for a API Master Liquid Test Kit.

 

No, I do not have an ammonia test. I use a 6 in 1 test strip.

Test strips are more expensive in the long run than liquid test kits plus they're less accurate than the liquid ones. Plus as you've found the strips don't include an ammonia test.

What were your exact results from the strips?

 

Interesting...I always heard that helped the fish adjust better.

The store water can contain extra ammonia, nitrites, nitrates, and parasites. Never add any. It helps to add the tank water into their bags while they're floating.

 

Interesting...I always heard that helped the fish adjust better.

Aquarium water is usually always heavily medicated. But the bacteria is still there. There are more cases than you can count of ich outbreaks caused by fish store water. It's just safer not to. Let them float for a while, then open the bag, put a little of your water in, then more, until the bag is level with your tank and can swim out. Keep as much of the fish store water in the bag as possible.

Ammonia could be your problem, but also test strips are inaccurate. I would go for a API Liquid Test Kit

By "liquid test kit" I believed Planted Aquatics is also referring to the API Master Test Kit, just to clear up any confusion.

When I was younger and knew nothing about fish, I had a couple of Mollies as well.

I can confirm that they do eat their young - my female Mollie had babies, and miraculously one survived until adulthood.

I would say you should get one of those little clear plastic breeding boxes for your pregnant Mollie, and then you can put her back in the tank when she gives birth and you can take care of her young.

unless - are the babies just running all around the tank already?

 

I want to jump in here. The other issues have been addressed. Unless I missed it no one asked what kind of minnows were they? If they were WCMM (white cloud mountain minnows) they would not be compatible with mollies. WCMM need water in the very low 70's and upper 60's in temp. Mollies like the upper 70's.

A very well planted aquarium is better than a breeding trap if you plan to keep them in the same tank. Mollies are prolific, you are better off with survival of the fittest or you will soon be up to your gills in babies. In our 150 tall we have several lady mollies and one male. the other fish in the aquarium keep the numbers in check. The ones that make it are the smartest and strongest.

 

When I was younger and knew nothing about fish, I had a couple of Mollies as well.

I can confirm that they do eat their young - my female Mollie had babies, and miraculously one survived until adulthood.

I would say you should get one of those little clear plastic breeding boxes for your pregnant Mollie, and then you can put her back in the tank when she gives birth and you can take care of her young.

unless - are the babies just running all around the tank already?

I just separated out all the adult mollies. so there are just the mollie fry and minnows in my big tank

They are zebra danio minnows. I thought they'd be alright

Test strips are more expensive in the long run than liquid test kits plus they're less accurate than the liquid ones. Plus as you've found the strips don't include an ammonia test.

What were your exact results from the strips?

Negative for nitrites, nitrates. pH around 7.5. water hardness around 40.

 

Do you rinse or change your filter media? No nitrates indicates that your tank isn't cycled.

What's the pH?

 

Do you rinse or change your filter media? No nitrates indicates that your tank isn't cycled.

What's the pH?

7.5. and there clearly are nitrates but the strips say they're less than the 2nd value

 

Oh that's good! If it was 0 it would have been a possible concern

 

Oh that's good! If it was 0 it would have been a possible concern

Yeah, I just know they're low but I don't have an exact value.

 

I still recommend testing your ammonia just to be sure it's zero

 

I still recommend testing your ammonia just to be sure it's zero

Update: took water to the store today to get tested (a proper fish store, not petsmart). the water was FINEEEEEE. Turns out, 1) the minnows we had were probably diseased. and 2) the mollies were probably in pH shock bc our water was more neutral than petsmart water.
That being said, we are still missing a mollie. WHERE IS SHEEEEE

 

Did they give you the actual results or just say it was fine?

 

Did they give you the actual results or just say it was fine?

Ammonia was 0, pH was 7, nitrates were 5ppm, nitrites were 1ppm

 

Nitrite at 1ppm is not fine. That's very toxic!