Fish Swimming Patterns

Question
Hello,

I have two Dalmation Mollies, one Silver Molly, and two Velvet Wag Swordtails in a 20-gallon tank. I am fairly new to aquariums and have been trying to learn on the fly. One thing just about everyone says to look out for is odd swimming patterns. The only problems is EVERYTHING seems weird to me!

I have been having problems with high Ammonia levels, and, consequently, high Nitrite levels, and have been doing frequent water changes (25-30% every day or two) to try and rectify the problem. In the meantime, I'm not sure what are weird swimming problems to look out for.

The female swordtail and one of the dalmation mollies have been hanging around the filter. That same molly also just today started to spend a lot of time "vertically" with his mouth towards the top of the tank. Other times, they seem kind of lethargic and content to hide in holes or behind the fake bridge, but I'm not sure what is a good or bad level of lethargy. Any help? Are there smoking guns here?

Thanks.

Answer
Bryan,
If you did not cycle the tank before you put the fish in, they are suffering from ammonia and/or nitrite poisoning. Tanks need to go through the 6 week cycle process because during this time, the tank goes through two bacteria blooms. The first bloom is the bad stuff that will make a fish ill and eventually die. The second bloom is the good stuff that both the tank and fish need to be healthy. I would test the water everyday and depending on the reading, do a water change. That is the easiest and safest way to bring the ammonia and nitrites down. The vertical swimming is not a good thing. It could be swim bladder disease or it could be showing signs of ammonia poisoning. If it is swim bladder, it is easily taken care of by fasting the fish for two days. On the third day, him them a shelled cooked pea, then fast again for 2 days. Swim bladder comes on by over feeding and if the water is not clean, it can make it worse. Also, your molly is a brackish fish. This means, they like some salt in their water. Also make sure there is a heater in the tank, and have is set between 78 and 82 degrees. They are tropical fish so they need warm water.