New Fish Mom
Hello, everyone! I am new to this forum, and new to being a fish/crawdad owner/ inadvertent breeder. We set up our first aquarium in December 2011 for our daughters' Christmas present of crawdads. They love catching them in the summer, so we thought how fun to watch them live and grow. We added fish a couple weeks later, and as deaths have occurred. We now have a twenty gallon tank housing 4 crawdads - 2 adult and 2 juvenile, as well as recent group of newly hatched baby crawdads. There is also one female gold dust molly in the tank, who recently also gave birth again, which was a surprise since we haven't had a male in the tank for about a month now. He died as did the other female molly who was in the tank. We also have a 10 gallon fry tank set up with 15-20 fry from both female adults, and a juvenile crawdad.
I'm still very new to this process, but we try to do water changes every week, and feed them only in the mornings. I have recently read that mollies will eat vegetation like peas, green beans and lettuce, so I am trying to add small amounts to the tanks. The crawdads are supposed to be able to eat these items too. We also feed them tropical flakes, shrimp pellets and bottom feeder sinking food tablets.
The water temperatures, without a heater, are between 75-80 degrees F, without much fluctuation. When we first set up the tanks, we were only adding water conditioner as well as bio-boost. Recently, a local pet store recommended adding aquarium salt as well, which I have done, but only with water changes.
I am concerned about the adult molly. Due to her odd behavior lately, my husband named her Nimrod. She swims erratically around the tank, hides occasionally underneath the crawdad log, rarely eats much, and almost appears pregnant again. I'm not sure if she is exhausted since she lives with crawdads, or if she is sick. When she is at the top of the tank, her dorsal fin is laying flat on her back, and her tail fin appears straight instead of fanned out. The last fish that died had an odd body curvature develop and dark spots appeared on her back (she was a very pretty Panda Moon molly). I had the water tested, and everything was fine then. Is there something I need to do?