In freshly caught specimens the sexes are difficult to differentiate between, even in the breeding season. The males may give themselves away perhaps with their blue corneas or smaller size. The well known reddened breast of a courting male is completely obliterated by black-spot in most cases, at least initially. In addition to this almost overwhelming parasitic burden, many have distended abdomens which I initially took to be females with roe but later become suggestive of intestinal worms. Deformities are not uncommon, the spine often deviating grotesquely or the jaw distorted.
Most specimens seem malnourished looking wasted despite their voracious appetites.
This makes them easy to catch. Shoals In June the shallows of the lagoon abound with fry swimming in shoals. I caught about 30 of them to see if I could rear these at home and observe them. At the time of capture the average length was 7 mm. It was not possible to tell the age but they are known to start shoaling at about two weeks.