I'm pretty sure my molly is in the process of dying..last night it was having a lot of trouble staying off of the bottom of the tank, and would often roll onto its side at the bottom for a few seconds. It was swimming very weakly, and this morning I noticed it with its head on the bottom and tail in the air and just spinning around a little bit. It's really not moving much. I feel like I should take it out of the tank, but it is currently hiding somewhere and I can't see it. I'm afraid that if I leave it in there too long, what ever is happening to it may spread to the other fish?
I have no idea what is causing it to behave like this though. My tank is 30 gallons with a tetra whisper 30 filter. It has been running with at least 3 fish in it sense thanksgiving, so a little over a month now, and it ran without fish in it for 2 weeks prior to that. I check the ammonia levels every day, and they're at 0. I haven't checked nitrites or nitrates in a while, but I plan on doing that today to try to diagnose this. The only thing that I can think of is that (I know it was too many all at once.. :/ ) but I added 6 fish to the tank on monday, and it's the only thing that I can think of that would have caused something like this to happen to one of my mollies, because it's really the only thing that has changed in my tank.
The other fish all seem to be doing well, acting normally. I have a baby in my tank and it is doing fine, the same as it always has been doing. I figure that if something was wrong with the water, it would probably affect the baby first wouldn't it?
My tank currently has: 2 dalmation molly's, a balloon molly, a silver molly (this is the sick one) (those are the four fish that have been in the tank for a while), plus the 6 I just added: 3 fancy guppies (one male, two female) and 3 sunset fire platy's (one male two female). One of the female sunset fire platy's was actually giving birth last night too, I saw at least two baby's swimming around her while she was wiggling around in the same spot for a while. Correct me if I'm wrong but I remember reading somewhere that fish won't give birth if they're stressed or something, is this right? If it is, it means that the new fish (at least that particular one) all feel comfortable and are fine with the water, doesn't it?
This is my first fish tank, and I'm just trying to figure out what I may have done wrong so that something like this doesn't happen again. Thanks for any help or insight you may be able to offer.