I do not think that this is a striated heron. Look instead at the black-headed heron ( Ardea melanocephala). The striated heron is much smaller, has a proportionally shorter neck, and a thinner bill. It is definitely a 'small heron', more like a black crowned night heron, for instance, than a grey heron.
I dont think that this is a rainbow trout. It looks more like a brown trout. An easy way to tell them apart is the presence of spots on the upper half or the tail. Rainbow trout also have smaller and more frequent spots that are more like flecks. nice picture, nonetheless. It must have been a wonderfully clear stream
Apparently this particular animal had been released into the wild and therefore had been sexed. It was also nearly fully grown at just under 2 metres. The guides in the area seemed to know many of the crocs in the area, and even had names for them, which was quite interesting.
This looks like the discarded pupa of a ladybird, perhaps Harmonia axyridis, or the harlequin ladybird. It was introduced to the USA several times in the 20th century, and since the '80s, has managed to spread all over the country. Here in Britain, they are regarded as a serious pest, and are quickly out-competing our native species.