Leopardess said:It seems like you already know what you plan to do. Are you really open to listening to what we are saying?
If nothing else, a male and a female in that tight of spaces will likely not get along.
Further, there is just not enough room. Period. There is no "buts" about that. 2.5" is STILL too big for a bowl, even if it's not full size yet.
Nitrate at 40ppm is considered on the high side, not the low side. You want your nitrates to basically never go above forty, preferably under 20, closest to 0 as possible.
Reducing your water changes is just plain foolish, I'm sorry. In a tank with no filter that's just asking for trouble.
Paradise fish are notorious jumpers, too, and most bowls don't have any covers.
Here is an excerpt from Mongabay which is very reliable:
"20" (50 cm) or 10 gallons (38 L) is adequate for smaller fish. Full grown specimen need a larger tank with a minimum size of 24" (60 cm) or 20 gallons (75 L). Provide retreats for the female. The tank should be well-vegetated. Fish prefer large tank with lots of open swimming area. A partial cover of floating plants is beneficial to aide in bubble nest building. The Paradise Fish is an well-known jumper, so the tank should be well-covered. "
I do think 20g is on the high side for an adult...but surely a bowl is too small. Especially considering there is no good reason to use one when you can get a 5g tank for about 5$ at Walmart.
Needless to say, you are 100% sure that the world is flat, PERIOD.