Topic: I have a fish aquarium with molly fish and one of them is acting sick and might be dying. It’s been acting weird and not swimming and laying on it’s side. What could be wrong with this molly? My aquarium has been running for around a year and seems healthy. The other fish are fine which is what leads me to believe it’s not the tank. Need help?

*Awarded Answer
Posted by Nick E: We see sick fish on this forum every single day. Don’t be too hard yourself. All a person can do is research on how to fix and hopefully learn for next time. Lets answer your question now.

Sick Molly Fish? Now Swimming or On It’s Side

The number one reason molly fish get sick is the aquarium not being properly cycled. People think the word “cycled” means they just let the tank sit.. that’s not it! You need to research and properly grow and establish bb bacteria. Buy an aquarium test kit and see if you have any ammonia or nitrites. If you do, then your tank is not properly established. Test kits are a necessity. Here is a picture and link:

You can also use the test strips. I advise you use the Tetra brand ones though because the other ones can sometimes be wrong or a bit misleading.. Hopefully this helps you. Re post your question with the water results and we can help you. Here is a picture and a link:

So i lost another molly last night that was swimming perfectly fine and had no signs of being sick. Im so frustrated that i keep losing fish should i empty my tank and wash everything and put it back in idk what to do at this point.

My tank is cycled i finally got my ammonia down but now my fish are dying off.

While you should continue to find out if there is a problem. The first thing I told my daughter when she wanted to get fish was, they die… sometimes for no apparent reason and that she should be prepared for that.

Put it together the week after Christmas and didnt put fish in it until a week after it was set up

i know like ive said on other posts ive put out is the pet store told me it was fine to out fish in it this is my first tank and am learning as i go im sure many people are. My husband bought it for me for christmas and i set it up.

Tank does not look cycled, and fish were put in too soon. I will also suggest that test strips are not very accurate. When you get a chance get the API master test kit (sometimes on sale at Amazon for $15 or so) as it will give you more accurate readings than test strips.

I agree with the tank not being fully cycled. Does anyone have any suggestions for on some good bacteria for her tank to help with the process? I use sponge filters in all my tanks…therefore if I need to establish a tank quick I will rotate those. Not sure what to do without that besides wait to add fish?

I think the pet shop had a poor quality fish. I use Seachem Prime and Stability in a new tank add fish a few hours later and that was two months ago. Most guppies and mollies are hardy compared to guppies.

uve already mentioned uve had amonia so that tells me ur not cycled. U need to track it amonia every day untill its properly cycled. Quick start by api or stability from seachem r 2 readily available bacteria supplements. But my time proven favorite is a good dirty piece of filter media from a clean established tank stuffed inside some clean media.

I personally think testing a waste of time. No matter how much you test anything can happen.

I dont reccomend not testing…. obviously tank maintainance is important. But u should be testing regularly. As tanks age chemistry changes ph can alter. Theres a lot going on.

If u dont want to use one that’s ur choice. But I dont feel u should reccomend that as advice to potentially new and unkowledged aquarists. Please and thank u.

Then how do you know if your fully cycled ? I have been doing water changes every other day the only thing that helped with was the amonia is finally at 0.

Mollies also do better in harder water. If you have soft water they may not be thriving. Especially if any other water quality issues too.

I use guppies and mollies to cycle my classroom tank. And YES, I purposefully start it with a heavy load of fish – in order to get strong cycle test results for student study. I rarely lose any fish during those three weeks. Pictured tank is on week 2 after setup. About 20 adult fish and countless fry.

That said, at home on a different water utility, I have a hell of a time keeping tank water suitable for fish. My work water is HARD water, home water is SOFT water. So I have now resorted to taking empty gallon hugs to work, filling them, and changing our my home water with city water. So it maybe your tap water. If you have soap scum problems in your shower – you likely have soft water.

well I just “culled” the first molly juveniles I’ve had owning them… it was only 4, but it wasn’t as bad as I was fearing. I took a gallon bag of aquarium water and netted the 4 from the tank into the bag and set the bag upright in an empty container. I added 4 or 5 drops of 100% clove oil to a random bottle of water I had to dilute it and poured a little bit of that water mixture into the bag over about an hour. I’ve done this with other fish that were sick before, it seems to be relatively peaceful for them and less graphic than smashing them with a hammer, which I do still consider humane because of the quickness of death, but I don’t like having to do that. after about an hour they become listless, stop swimming, then “pass away.”

If you can figure out how to safely ship them I will gladly take all the unwanted babies you have. I am newer but do have 5 tanks set up and I’m sure I could find them all homes relatively easy. I have tons of people wanting my babies as is.

Knowing how to humanely cull animals is an important part of being a responsible owner/breeder. Anyone who has kept animals for a decent duration has had a critter they’ve had to cull for the health of the individual or the group. If you can’t do it yourself, make a plan with someone who can do it for you. You never know when you’ll need to do it, and possibly quickly.

Culling is a necessary evil of breeding tropical fish. I cull the sick, deformed and sometimes those that don’t meet the type I’m wanting to breed.

Maybe have a secondary tank set up with some angelfish or Baka sharks, would be a nice little snack. Though not as humane but cycle of life ya know.

I am new to this group, and read the rules recently. This type of post isn’t actually allowed. Any post about “causing harm to fish for any reason” including using them as feeders. Personally I disagree with the rule and think your post is fine. But technically it isn’t ok here. I belong to a freshwater fish group that has more open rules about these discussions.