Molly is dying :[

Major25

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.

Oldman47

Chances are quite good that you have sky high nitrites in the tank. It would be worthwhile to do at least a 50% water change with proper dechlorinator added right away. You are most likely in the second stage of establishing your cycle, the nitrite spike. Do not add fish until the cycle has finished, whether or not you lose any.
You need to be doing daily water testing and be responding to the readings with big enough water changes to actually make a difference. A simple one month of cycling is enough to get past most of the ammonia part of a cycle but is just enough to put you smack dab in the middle of the nitrite spike. Even if your tank had been fully cycled, the 3 fish in it would in no way prepare the filter for an influx of 6 more fish plus the fry. You need to get the tank cycled and then only add a percentage to what is already in the tank, not double or triple the stocking overnight.
The only thing that may save you is that the tank is large enough to help dilute some of the poisons that are being generated in that tank. That can give you a bit of breathing room to get things right, after the first big water change.

Major25

Yea, I'm sure you're right..I was monitoring the ammonia so much, I figured that I'd see the ammonia spike, and then I would begin monitoring the nitrites, I guess I should have just been monitoring them both the whole time, It's my fault really I feel bad for the fish..I will test the nitrites as soon as I get home and do water changes every day until I see the nitrites go down, that must be what it is. I knew I shouldn't have added so many at once, but the person at the store made it seem alright. Anyways, thanks for the advice, I'm going to take you up on it as soon as I get home and once I get it tested and do the water change, I'll post back here with what I find for readings.

Major25

Just got everything tested, ammonia nitrites and nitrates are at 0, but my ph was very high the guy said, he said it was about 7.8. He told me that the best way to lower the ph was with a large water change, vacuuming the gravel and feeding them a little less, so that's what I plan on doing. Are there any other suggestions for safely lowering and keeping down my ph levels?

Oldman47

There is no need to start lowering the pH for a molly. Mine always live in 7.8 pH water and they thrive in it. In fact, a molly will be much better in 7.8 pH water than in 7.0 pH water. If you are being advised to do a water change, the chemistry readings you got are just not believable. If both ammonia and nitrites were processing properly, it would be driving the nitrates up, not leaving them at zero. I am betting the shop used a paper test strip instead of really testing the water, or maybe they just went out of sight for a minute and came back telling you everything is fine. Test strips are notorious for giving bad readings and it takes a fair amount of experience just to read them when they are all that you have. You need to get a proper test kit for yourself that uses the little test tubes.
I will agree with one bit of advice the shop gave you, do a few very large water changes and the fish should start to look better. Try doing the first change of no less than 75% of the water. Make sure you unplug the filter and heater, you don't want to ruin them by letting them run out of the water.