guppy problems

#1
one of my 2 guppies the male is on the bottom and hes not swimming and it looks like his stomach is bloated. He looks all dead but i can tell hes alive cause his gills and he also swims up but spends more time on the bottom. A couple of days prior i shut off the biowheel cause i didnt want the fry to get sucked up the tube because there is a preggo female. Water looks clean
 

#14
still... fish create amonia by breathing, and the fish waste rotting, then these little bacterias eat those and make nitrites, and a new set of bacteria eat those and make nitrates... in the wild, nitrates just get washed away... but since it all stays inside a glass box, you need to do water changes to keep them down. since the tank is (not new) but newly set up... i think... but any ways, a month is way too long to go with out a water change. i suggest you do a large one, and fast. also, i am going to ask again... DO YOU HAVE A TEST KIT?