| Thrusting was defined as attempts to introduce the male's gonopodium into the female's genital opening. |
| Most of the fin structure in the male fish is modified into bone, comprising the gonopodium. |
| In mosquitofish, once the testes mature, a male's testosterone production soars, a gonopodium develops, and then growth ceases. |
| The structure of the gonopodium of 10 mature males examined matches the description by Rosen, and most specimens display diagnostic characters mentioned by Miller et al. |
| Mating occurs when the male swims up to the female from behind, swings his gonopodium down and onto the female's egg spot, and delivers sperm. |
