Hi! I have 3 mollies, with my figure 8 puffer and 2 bumblebee gobies in a custom made 20 gallon long thats 3 feet long. 1 female dalmatian butterfly lyretail, and a male and female yellow ballon butterfly mollies. The tank is densely planted and is at brackish, with an SG of 1.007. Lately my female black molly has been nuzzling my males belly. It doesnt seem to be aggressive, but is it normal? Also will different mollies crossbreed? For example will a sailfin mate with a balloon?