To throw a spanner in the works!
Warning: Boring info below
-Western Blue Groper (Achoerodus gouldii)
Color: Juveniles grey to green, sometimes with yellowish or whitish spots scattered on back. Females grey to red. Males grey to blue.
Eastern blue groper (Achoerodus viridis)
Colour: juveniles grey with with several yellowish spots scattered on back. Females red to brown. Males grey to blue.
As you can see the color is almost identical red-red, grey-grey, blue-blue. Both species have the same body shape eg 32-41% body depth against there SL(standard length). So if colour and body shape are similar then how do you distinguish difference under water?
The only difference is the number of scales.
Western blue groper: Lateral line with 33-37 pored scales: scales above lateral line 7-7.5
Eastern blue groper: Lateral line with 41-45 pored scales: scales above lateral line 9-10.5
Some people might have their ways of telling the two species apart apart from the scales and I'm not saying their wrong and im not saying that what all experts say is the bible. But I tend to lean a 'little' bit towards the people that have spent most of their lifetime researching and then putting a together a 900pg book which defines key biological characteristics between species.
Just my two cents
Don't worry I'm confused as well. Anyway thank christ it wasnt a coral trout
otherwise who knows how much more garbage I'd be writing.