I'm concerned about one of my Black Mollies, it's just lying at the bottom of the tank. Does anyone know what could be wrong?

What are your nitrate and ammonia readings?

You also said they were new, how did you acclimate them?

I don’t know what my nitrate and ammonia readings are, nor did I take any special steps in acclimating them because the store I got them from made them seem very much like goldfish as far as care goes. I live in Florida and we do have harder water than most other parts of the country. To acclimate them I just set up the tank (got it to the right PH, etc) and let the filter run for a while, and then put them in. I got them about a week ago.

Did you let the tank cycle prior to putting said fish in there?

If not, chances are your going through an ammonia/nitrate spike right now. This is likely the reason your one fish seems ill. I know the other is still swimming around fine, but what effects one fish doesnt always effect the other. Another thing, ALWAYS ACCLIMATE FISH. No matter what it is, acclimate it, it will only increase the chances of the fishes survival. I personally like to drip acclimate everything, but you could just float the bag in the water for a half hour or so until water temp is the same and then remove the fish from the store water and put it in your tank.(never put store water in your tank, you dont know their water quality or what kind of parasites you can be bringing along.)

I recommend you buy yourself a test kit for your tank, you dont need anything fancy, just the test strips will do. If you dont feel like putting out that extra money, most stores will test your water for free if you bring them a sample.

One last thing, never listen to what your told in fish stores. 90% of the people have no clue wtf they’re talking about. Always research any fish your considering buying before you actually go to the store to buy it, so that you can insure it will not only live in your tank, but thrive.

Oh, ok, by ‘acclimate’ I thought you meant something more complicated. Yes, I did float the bag in the new tank before putting the fish in, and I did not put any of the store water in the new tank. That said, could it still be a nitrate/ammonia spike? I figure I should invest in a test kit (I’m just assuming that this is similar to a PH test kit) anyway, but are there other things I should be considering, such as ick/ich?

The sick fish, I should say, isn’t completely immobile or swimming upside down or anything, but it is visibly bloated and far more sedentary than the other and when it does venture out of its corner the other fish follows it around. This is what led me to consider pregnancy.

I just want to make sure that I have all my bases covered and am treating the broadest range of things, because I’d hate to just become convinced that its one thing and it turn out to be another.

@uberbatman Thank you so much for your help though, you’ve been great and I can tell you know what you’re talking about =]. I apologize for sounding frantic I just really don’t want these fish to get sick or die. If there’s anything else you’d recommend I’d really appreciate it. As far as the pet store people, I completely agree. I also have a 10 gallon tank with mixed species back home and taking care of it has taught me a lot. They made it sound so easy but I thought it’d be better if I invested in things like a PH test kit, for example. I’ve never had to worry about nitrates and ammonia though, so I didn’t think to take that into consideration with the mollies.

Thanks again!

@amaris I dont think its ich, you’d be noticing white blotches on the fish. It can be kind of tricky figuring out exactly what is wrong with fish, especially live bearers that dont seem overly hardy in my experience.

As far as the testing goes, you definitely want to be testing your other levels on a somewhat regular basis aside from just PH. You can get something like this that will test your basics all on one test. It doesnt however test for ammonia. Ammonia normally isnt a problem, just during that first cycle it spikes. If your going to have another ammonia spike down the road, other levels will be off such as nitrates.

Nitrates are something you always want to be mindful of. Nitrates are waste material. They will build up in your gravel over time.(thats why its always important to clean this real well while doing water changes.) Nitrate levels over 20 are dangerous to fish. Nitrates should be kept at 0 but this hardly ever happens, 10 isnt bad though. Another thing about high nitrates is it leads to high algae growth. So by keeping your nitrate level low, you also keep the algae growth to a minimum. high phosphates also lead to algae growth, but you shouldnt need to worry about that.