I have had my tank set up for around 20 weeks now, it has 1 plecko, 2 red eye tetra, 2 silver mollies, 1 golden sunshine guppy, 1 red plattie and 1 catfish, the silver mollies, both female were introduced about 5/6 weeks ago, 1 of them 3 weeks ago started to swell is now huge and looks bigger...