I recently purchased two Dwarf Puffers for my new Fluval Flex 9g tank and I'm having trouble sexing them, they both seem to have traits attributed to both sexes so I'm hoping to get some outside opinions.
Puffer #1 I refer to as "yellow" this puffer is:
- Large, about one full inch
- Faded and more yellow pattern and belly
- No eye wrinkles
- Very pronounced dark red belly line w/ "goatee" that does not fade
Puffer #2 I refer to as "white" this puffer is:
- About 3/4" long
- Much brighter with a white belly
- Has a faded belly line that is sometimes nearly invisible but always gets darker when feeding and being aggressive to the other puffer
- Clearly visible iridescent blue eye wrinkles
Here are some pictures to help:
Picture 1: "White"

Picture 2: "Yellow"

Picture 3: White in front showing eye wrinkles, yellow behind

Picture 4: White on left showing faded belly line, Yellow on right showing pronounced dark belly line

Please let me know what you think and why, thanks for the help!