I am new to guppies and I just bought 6 of them to go into one of my ten gallon tanks. He was swimming slower than usual this morning so I tested my water and it seems fine. My water temp is at 78°. I just went to go to bed and shut off their aquarium light and noticed him hiding in the plants and laying on the gravel. My other 5 guppies are acting normal and one had given birth to 15 fry on the 17th, 3 died on the first night, but they also swam sideways and looked weird when they came out. The female also swims near the bottom and still has her gravid spot and squared off stomach so I am not sure if she is going to have more. It has been atleast 24 hours since the last fry came out. Everytime I encourage the male (I think he is a blue multicolored guppy, but I forget what exactly.) to swim up, he just floats back down. He is also breathing pretty fast. I am about 80% sure he will pass away tonight, but I just have no idea what I could be doing wrong.