can 金菠蘿 in 4 cm to have bb?

i have 4 金菠蘿 and a 雞泡魚,they have not to fight. 1 of 金菠蘿is big and another are smaller.
i have saw them to kiss but a month ago they do not kiss again. are they begin to have bb?that (them) is the smaller 金菠蘿.

pleas use 中文 to awnser