Strange Mollie behavior

Question
I have had my 10 gallon tank set up for about 2 months now. I have
3 tetras and one mollie. Recently, the mollie has been acting
erratically, swimming in short bursts and swimming furiously up
and down the tank walls. Sometimes, she hangs out near the
bottom of the tank in one spot, flapping her fins very fast. She
looks okay, but doesn't seem to be eating as much as usual. The
other fish, however, seem to be doing just fine. The pH level is
about 6.5. I believe that ammonia and nitrite levels are normal.
Could she be pregnant? Any advice would help. Thanks.

Answer
Hi Laura;

Molies are very sensitive to the quality of the tank water. You need to make some partial water changes so she feels better again. All tanks need weekly 25% changes anyway so if you haven't been, now is a good time to get it started. Replace 25% of the water every day for the next 4 days to get the water corrected without stressing the fish too much. After that, a weekly water change and gravel vacuuming every 2 to 3 weeks with a weekly change is all that's needed. Here is an excellent article on mollies that will help you with their care and feeding;

http://www.aqualink.com/columns/k-livebearer3.html

Look for tiny white salt-specks on her. Sometimes the behavior she is showing means there are parasites involved too. There are remedies at the local fish store. The tank still needs to get some partial water changes though. Ick attacks when fish are under stress, and water quality issues are a major source of stress in fish.

I hope she feels better soon......

At Your Service;
Chris Robbins